Organic trace minerals and 25 ... - Semantic Scholar

Organic trace minerals and 25-hydroxycholecalciferol affect performance characteristics, leg abnormalities, and biomechanical properties of leg bones of turkeys1,2 P. R. Ferket,*3 E. O. Oviedo-Rondón,* P. L. Mente,† D. V. Bohórquez,* A. A. Santos Jr.,‡ J. L. Grimes,* J. D. Richards,§ J. J. Dibner,§ and V. Felts# *Department of Poultry Science, and †Department of Biomedical Engineering, North Carolina State University, Raleigh 27695; ‡Department of Health and Biomedical Sciences, Florida Hospital College of Health Sciences, Orlando 32803; §Novus International Inc., 20 Research Park Drive, St. Charles, MO 63304; and #Goldsboro Milling Co., Goldsboro, NC 27532 BW. Only MIN significantly improved feed conversion ratio through to 20 wk of age. Cumulative mortality at 3 wk of age was greater among the MIN birds, but it was lower by 20 wk (P = 0.085). The MIN decreased the incidence of varus defects at 17 wk of age; shaky leg at 12, 15, and 17 wk of age; and valgus defects at 15, 17, and 20 wk of age. There were no MIN × HyD interaction effects on individual gait problems. Maximum load and the bending stress required for tibias to break in a 4-point assay were increased with MIN supplementation, especially when HyD was also added. Maximum shear stress at failure of femoral bones in a torsion assay was increased by supplementation with both MIN and HyD together. Dietary supplementation of MIN and HyD may improve biomechanical properties of bones. Dietary MIN supplementation may improve feed conversion of turkeys, likely by decreasing leg problems.

ABSTRACT Leg problems and resulting mortality can exceed 1% per week in turkey toms starting at approximately 15 wk of age. Dietary supplementation of organic trace minerals (MIN) and 25-hydroxycholecalciferol (HyD) may improve performance, decrease incidence of leg abnormalities, and increase bone strength. Nicholas 85X700 toms were assigned to 4 treatments consisting of a factorial arrangement of 2 concentrations of MIN (0 and 0.1% of Mintrex PSe, which adds 40, 40, 20, and 0.3 mg/kg of Zn, Mn, Cu, and Se, respectively) and 2 concentrations of HyD (0 and 92 μg/kg of HyD). Diets were formulated to be equal in nutrient content and fed ad libitum as 8 feed phases. Feed intake and BW were measured at 6, 12, 15, 17, and 20 wk of age. Valgus, varus, and shaky leg defects were determined at 12, 15, 17, and 20 wk of age. Tibia and femur biomechanical properties were evaluated by torsion and bending tests at 17 wk of age. There were no treatment effects on

Key words: turkey, organic trace mineral, 25-hydroxycholecalciferol, leg problem, bone 2009 Poultry Science 88:118–131 doi:10.3382/ps.2008-00200 Vaillancourt et al., 1999). Although lameness and bone fractures generally occur during the last few weeks before market, the underlying bone developmental abnormalities that lead to these events often occur during the first few weeks after hatch (Vaillancourt et al., 1999, 2000; Farquharson, 2003; van der Eerden et al., 2003; Huff et al., 2006; Dibner et al., 2007). The increased incidence of lameness in recent years (Vaillancourt et al., 2000; Julian, 2005; V. Felts, unpublished data) may be due in part to the change that has taken place in overall body structure and conformation of fast-growing, high-breast meat yield birds (Abourachid, 1993). Breast muscle yields have increased dramatically in recent years, thereby moving the center of gravity of the bird forward (Abourachid, 1993; Corr et al., 2003a,b; Havenstein et al., 2007). This body conformation characteristic of modern turkeys affects

INTRODUCTION Leg problems are a primary concern for turkey production worldwide. These problems include lameness, bone developmental disorders, and bone breakage. Lameness is common in poultry selected for rapid growth, and its incidence within a flock can exceed 15% (Lilburn, 1994; ©2009 Poultry Science Association Inc. Received May 20, 2008. Accepted September 8, 2008. 1 Data in this paper were partially presented at the Poultry Science Association Annual Meeting, Edmonton, Canada, July 16–19, 2006 (Abstract 38), and at the International Poultry Scientific Forum, Atlanta, Georgia, January 22–23, 2007 (Abstract T142). 2 The mention of trade names in this publication does not imply endorsement of the products mentioned nor criticism of similar products not mentioned. 3 Corresponding author: [email protected]

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gait patterns (Resch-Magras et al., 1993; Corr et al., 2003b) and imposes considerable stress and strain in femur and tibia bones, thus affecting bone development and increasing the risk of fractures. Femoral spiral fractures and tibia fractures are common pathologies in toms between 15 and 18 wk of age (Vaillancourt et al., 1999, 2000; Julian, 2005). Crespo et al. (1999) reported femoral spiral fractures in turkey breeders and associated them with biomechanical properties (Crespo et al., 2000), microstructure, and trace mineral content of bones (Crespo et al., 2002). In tom flocks of high average daily gain (>280 g of gain/d), mortality rate associated with leg problems may be as high as 5% of a flock and can occur by exsanguination when the femoral artery is severed by a spiral fracture fragment of the femur or when downer birds are killed by aggressive birds in the flock (Crespo et al., 1999; Julian, 2005). Leg problems of downer birds may include valgus-varus deformations or general leg weakness (Vaillancourt et al., 1999, 2000; Julian, 2005). Leg problems cause economic losses to producers, because birds with these abnormalities exhibit decreased feed intakes, lowered growth performance, increased mortality, and greater rates of downgrades and condemnations during processing (Bennett et al., 2002; OviedoRondón et al., 2006a; Dibner et al., 2007). Several nutrients can affect skeletal development and lameness in poultry as reviewed by Whitehead (2002) and Oviedo-Rondón et al. (2006b). Vitamin D and its metabolites are perhaps the most extensively studied nutrients with respect to bone development in poultry. Vitamin D3 is important in Ca and P absorption and metabolism, and a deficiency can lead to the failure of mineralization of growing bones, leading to retarded growth, leg weakness, and rickets (Oviedo-Rondón et al., 2006b). Fritts and Waldroup (2003) evaluated supplementation of different concentrations of cholecalciferol (D3) and 25-hydroxycholecalciferol (HyD) in cornsoy diets and found that the incidence and severity of tibia dyschondroplasia were significantly lower among broilers fed diets supplemented with HyD. Trace minerals often are less recognized as being important for proper bone development. Nonetheless, a sizeable body of literature underscores the importance of Zn, Cu, Mn, and Se among other trace minerals on bone growth and strength (Dibner and Richards, 2006; Oviedo-Rondón et al., 2006b; Dibner et al., 2007). Furthermore, these trace minerals interact with each other and with 1,25-dihydroxycholecalciferol during bone formation, modeling, and remodeling (Beattle and Avenell, 1992). Trace minerals are most often supplemented to diets as inorganic trace mineral salts (oxides or sulfates), and the mineral requirements for poultry have been established using these inorganic sources (NRC, 1994). However, the bioavailability of inorganic trace minerals can be low and variable due to a variety of nutritional antagonisms, including phytic acid, fiber, Ca, and P

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(Wedekind et al., 1991; Bremner and Beattie, 1995; Underwood and Suttle, 1999; Tamim and Angel, 2003; Leeson, 2005). Trace mineral (Zn, Cu, and Mn) complexes or chelates with an organic ligand (i.e., amino acid, organic acid, or protein digest) can confer stability of the trace mineral in the upper gastrointestinal system, thereby avoiding mineral losses to antagonists and potentially improving trace mineral bioavailability (Miles and Henry, 2000). Indeed, these organic trace minerals can have greater mineral bioavailability than inorganic trace mineral salts (Paik et al., 1999; Cao et al., 2000; Guo et al., 2001; Leeson, 2005; Predieri et al., 2005; Yan and Waldroup, 2006; Wang et al., 2007). In addition, organic sources of Se (as selenomethionine from high-Se yeast) can be more bioavailable than inorganic Se (Rayman, 2004; Payne and Southern, 2005a,b). Because of their critical roles in bone development, we hypothesized that the use of more bioavailable forms of vitamin D (i.e., HyD) and trace minerals [i.e., Mintrex (MIN)] may improve early skeletal development and decrease subsequent leg problems without compromising growth performance. The objective of this study was to determine the effect of dietary supplementation of MIN and HyD on the growth performance, incidence of leg abnormalities, and bone fracture resistance of Large White turkey toms.

MATERIALS AND METHODS Birds and Diets Eight hundred sixty-four male Nicholas 85X700 turkeys were obtained from a commercial hatchery (Sleepy Creek Hatchery, Goldsboro, NC) and randomly assigned among forty-eight 9-m2 floor pens with 18 birds per pen. Four experimental treatment groups were randomly assigned among 4 blocks (rows) of 12 pens in a curtain-sided house. The 4 experimental treatments consisted of a 2 × 2 factorial arrangement of 2 dietary inclusion concentrations of 25-hydroxycholecalciferol (0 or 92 μg/kg of complete feed) and 2 concentrations of MIN (0 or 1 g of Mintrex PSe/kg of complete feed). The diets were formulated to maximize growth rates, exceeding NRC (1994) recommendations. The 25-hydroxycholecalciferol was supplemented to the diet as the premixed product HyD (DSM Nutritional Products Inc., Parsippany, NJ; 183.2 mg of 25-hydroxy cholecalciferol/kg of HyD premix) at an inclusion rate of 0.05%. The dietary inclusion of Mintrex PSe (Novus International Inc., St. Charles, MO) provided per kilogram of diet 40 mg of Zn, 40 mg of Mn, and 20 mg of Cu as a complex with methionine hydroxy analog and 0.3 mg of Se/kg of diet as Se yeast. Mintrex PSe contains 54% by weight 2-hydroxy-4-(methylthio)butanoic acid (referred to as methionine hydroxy analog) as the chelating ligand, which has been reported to be fully available as a source of methionine activity (Yi et

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al., 2007). To ensure that all the diets were formulated to contain equal amounts of methionine activity, the addition of Alimet Feed Supplement (88% methionine hydroxy analog, Novus International Inc.) was appropriately decreased in diets containing MIN (Tables 1, 2, 3, and 4). Thus, slight changes in dietary mineral premix inclusion concentrations and other ingredients were made. For example, dietary inclusion of limestone varied as the concentrations of mineral premix (containing calcium carbonate as carrier) was modified to accommodate the MIN supplementation. Therefore, all diets had similar nutrient composition and the same concentrations of Zn, Mn, Cu, and Se, the difference being in the relative amounts of organic and inorganic (sulfate) forms. All of the experimental diets were pellet-processed (20-s steam conditioning at 80°C). The feed was fed in crumble form until the birds were 6 wk of age and whole 4-mm pellets thereafter until slaughter at 20 wk of age. Each replicate pen was equipped with 1 tube feeder, 1 Plasson drinker (Plasson Ltd., Menashe, Israel), and soft pine shavings as litter. To simulate industry conditions, the birds were placed 24 h after hatch and fed high-fat, nutrient-dense pelleted diets (Tables 1 to 4) until slaughter at 140 d of age. All of the birds were raised according to typical management practices. The birds received 23 h of incandescent lights from 1 to 10 d and natural lighting subsequently until the experiment was terminated at 140 d of age on February 7, 2005. The experiment reported herein was conducted according to the guidelines of the Institutional Animal Care and Use Committee at North Carolina State University. All husbandry practices and euthanasia were done with full consideration of animal welfare.

Performance and Walking Scores Individual BW and pen group feed consumption were measured on wk 6, 12, 15, 17, and 20. Incidences of leg abnormalities (valgus, varus, and shaky leg) and breast buttons were recorded on each weigh day. Walking ability score (3 = down and crippled; 2 = limited mobility with significant limp; 1 = mobile with mild limp; 0 = no leg-associated mobility problems) was evaluated by 2 observers who were unaware of treatments at 12, 15, 17, and 20 wk of age These 2 observers worked together to report walking ability score and incidence of leg abnormalities by consensus. Gait abnormalities may be due to many causes such as leg deformation, pain in articulations, and changes in body conformation (Abourachid, 1993; Resch-Magras et al., 1993; Corr et al., 2003a). Therefore, the gait of each turkey was observed, and those identified with a valgus or varus leg deformation were scored for severity as described above. The incidence of birds that exhibited leg tremors while walking or standing were classified as shaky leg as described by Julian (2005). Mortality rate and cause of mortality were recorded on a daily basis and

analyzed by period and cumulatively. Weights of all mortalities were recorded as they occurred to correct for feed conversion ratio (FCR).

Biomechanical Properties of Bone At 17 wk of age, 2 birds per pen (24 birds per treatment) were killed, and femurs and tibias were dissected and analyzed for biomechanical properties. Fracture resistance of turkey tibias was tested by 4-point bending using an axial servohydraulic load frame (858 Mini Bionix II, MTS Systems Inc., Minneapolis, MN). The tibias were assumed to have a hollow elliptical cross section with a uniform wall thickness as described by Cubo and Casinos (1998, 2000). The diameters of the major axis (medial-lateral direction) and minor axis (frontal-caudal direction) were measured, and bones were loaded with the resulting moment applied about the medial-lateral axis. The 4-point bending tests were carried out with a lower support span of 160 mm. The load was applied through 2 upper supports spaced 76.5 mm apart at a loading rate of 30 mm/min to failure. The cortical wall thickness was measured at 4 points along the cross section on each side of the failure to determine the mean thickness. The total force applied and the displacements of the upper supports were recorded. The different biomechanical parameters were calculated according to the following formulas: Area moment of inertia (Ix)

Ix =

3 3ù 1 é p ê rmajor (rminor ) - rmajor - t (rminor - t) ú úû 4 êë

(

)

(

)

where rmajor = radius of the major axis of the ellipse forming the outer cortical boundary, which is the axis about which the bending takes place; rminor = radius of the minor axis of the ellipse forming the outer cortical boundary; t = average cortical thickness. The applied moment (M) for 4-point bending: M = [Fmax (L1 − Lu)]/2, where Fmax = maximum applied force; L1 = lower support span; and Lu = upper support span and Maximum bending stress (σmax) = M(rminor)/Ix. Torsional properties of turkey femurs were tested using an axial-torsion servohydraulic load frame (858 Mini Bionix II, MTS Systems Inc.). Femora were assumed to have a hollow elliptical cross section with inner and outer edges forming similar ellipses. The ends of the femora were potted in epoxy (Bondo, Bondo Corporation, Atlanta, GA) to allow them to be secured into

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ORGANIC TRACE MINERALS AND VITAMIN D IN TURKEY DIETS Table 1. Experimental diets fed to turkeys from 0 to 6 wk of age, treatments 1, 2, 3, and 4 Prestarter1 Item

1

2

3

Ingredient Corn Soybean meal (48%) Poultry meal (60%) Poultry fat Dicalcium P (18.5%) Limestone Choline chloride (60%) l-Lys (HCl) Alimet l-Thr Salt Vitamin premix3 Mineral premix4 NaSeO3 premix5 Mintrex-PSe6 HyD7 Copper sulfate Coban-608 Total Calculated analysis ME, kcal/kg CP, % Lysine, % Met, % Met + Cys, % Thr, % Ca, % Nonphytate P, % Na, % Na + K − Cl, mEq/kg Added Zn, mg/kg Added Mn, mg/kg Added Cu, mg/kg Added Se, mg/kg

38.8 44.2 6.0 5.2 3.2 0.85 0.20 0.20 0.43 0.06 0.27 0.10 0.25 0.15 — — 0.06 0.05 100.00 3,100 28.5 1.80 0.82 1.25 1.15 1.45 0.85 0.18 258 150 150 145 0.3

38.9 44.2 6.0 5.2 3.2 0.92 0.20 0.20 0.38 0.06 0.27 0.10 0.18 — 0.10 — 0.05 0.05 100.00 3,100 28.5 1.80 0.82 1.25 1.15 1.45 0.85 0.18 258 150 150 145 0.3

38.7 44.22 6.0 5.2 3.2 0.85 0.20 0.20 0.43 0.06 0.27 0.10 0.25 0.15 — 0.05 0.06 0.05 100.00 3,100 28.5 1.80 0.82 1.25 1.15 1.45 0.85 0.18 258 150 150 145 0.3

Starter2 4

1

2

(% of diet) 38.8 43.7 43.9 44.2 40.1 40.1 6.0 6.0 6.0 5.6 4.4 4.4 3.2 3.0 3.0 0.92 0.91 0.91 0.20 0.20 0.20 0.20 0.30 0.30 0.38 0.42 0.37 0.06 0.07 0.07 0.27 0.27 0.27 0.10 0.10 0.10 0.18 0.25 0.18 — 0.15 0.00 0.10 — 0.10 0.05 — — 0.05 0.06 0.05 0.05 0.05 0.05 100.00 100.00 100.00 3,100 3,100 3,100 28.5 27.0 27.0 1.80 1.75 1.75 0.82 0.80 0.80 1.25 1.20 1.20 1.15 1.10 1.10 1.45 1.40 1.40 0.85 0.80 0.80 0.18 0.18 0.18 258 235 235 150 150 150 150 150 150 145 145 145 0.3 0.3 0.3

3

43.7 40.1 6.0 4.4 3.0 0.91 0.20 0.30 0.42 0.07 0.27 0.10 0.25 0.15 — 0.05 0.06 0.05 100.00 3,100 27.0 1.75 0.80 1.20 1.10 1.40 0.80 0.18 235 150 150 145 0.3

4

43.8 40.1 6.0 4.3 3.0 0.97 0.20 0.30 0.37 0.07 0.27 0.10 0.18 — 0.10 0.05 0.05 0.05 100.00 3,100 27.0 1.75 0.80 1.20 1.10 1.40 0.80 0.18 235 150 150 145 0.3

1

Feed offered to toms from 0 to 21 d of age at 1.5 kg/bird in form of fine crumbles. Feed offered to toms from 21 to 42 d of age at 2.0 kg/bird in form of coarse crumbles. 3 Each kilogram of vitamin premix (0.1% inclusion) supplied the following per kilogram of complete feed: vitamin A, 13,200 IU; cholecalciferol, 4,000 IU; α-tocopherol, 66 IU; niacin, 110 mg; pantothenic acid, 22 mg; riboflavin, 13.2 mg; pyridoxine, 8 mg; menadione, 4 mg; folic acid, 2.2 mg; thiamin, 4 mg; biotin, 0.253 mg; vitamin B12, 0.04 mg; ethoxyquin, 100 mg. 4 Each kilogram of mineral premix (0.1% inclusion) supplied the following per kilogram of complete feed: 60 mg of Zn as ZnSO4·H2O, 60 mg of Mn as MnSO4·H2O, 40 mg of Fe as FeSO4·H2O, 5 mg of Cu as CuSO4, 1.25 mg of I as Ca(IO3)2, 1 mg of Co as CoSO4. 5 NaSeO3 premix provided 0.3 mg of Se/kg of complete feed. 6 Mintrex PSe provided the following per kilogram of complete feed: 40 mg of Zn, 40 mg of Mn, 20 mg of Cu, and 0.3 mg of Se (as Se yeast). To compensate for the lower I contribution from the mineral premix inclusion, 1.3 g of Ca(IO3)2 was added per kilogram of complete feed. Mintrex PSe is a registered trademark of Novus International Inc. (St. Charles, MO). 7 HyD is a registered trademark of DSM Animal Nutrition Inc. (Parsippany, NJ). 8 Monensin. Elanco Animal Health division of Eli Lilly and Co. (Indianapolis, IN). 2

the load frame. Before they were potted, screws were driven into the proximal and distal ends of the bones leaving approximately 10 mm of the screw shaft exposed to help ensure that the ends of bones were tightly held within the epoxy. The distal end was held fixed in the load frame, and the proximal end was rotated in external rotation at a rate of 10°/s until failure. The applied torque and angular rotation were recorded. Cortical wall thicknesses were measured as was done for the tibia, and the radii of the inner ellipses used to model the cross section of the bones were calculated so that the average distance between outer and inner ellipse cortical boundaries matched the averaged measured

thickness. The different biomechanical parameters were calculated according to the following formulas: Maximum shear stress (τmax) = Tmax/Q where Tmax = maximum torque applied during test and

Q=

(

)

2

(

p rmajor (rminor ) 1 - k4 2

).

For similar ellipses: inner elliptical boundary = k × (outer elliptical boundary).

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Statistical Analyses All data were analyzed as a completely randomized block design using 2 × 2 factorial arrangement of dietary MIN and HyD supplementation as main effects. Pen means were used as the experimental units for all variables evaluated. Percentage of mortality and leg abnormality incidence data were transformed to the arcsine square root before analysis, and final data are presented as natural numbers. All measures of statistical significance were based on a probability of P ≤ 0.05 unless otherwise stated. Data were subjected to ANOVA using the GLM procedure of SAS system (SAS Institute, 2003). Means separation was accomplished

using Tukey’s multiple range tests when a significant F statistic was indicated by ANOVA.

RESULTS AND DISCUSSION Performance Independent of the exceptional growth rate observed in this study (>151 g/d), there were no significant treatment effects on BW at any of the observation times (Table 5). The growth performance of the birds in this study exceeded those typically observed in the field. In this study, BW at 20 wk of age averaged 21.2 kg, which was about 1 kg heavier than hatch mates grown

Table 2. Experimental diets fed to turkeys from 6 to 10 wk of age, treatments 1, 2, 3, and 4 Grower I1 Item

1

2

3

46.5 36.6 6.0 5.5 2.76 0.85 0.20 0.30 0.35 0.03 0.27 0.10 0.25 0.15 — — 0.06 0.05 100.00

46.8 36.6 6.0 5.5 2.76 0.85 0.20 0.30 0.30 0.03 0.27 0.10 0.18 — 0.10 — 0.05 0.05 100.00

46.5 36.6 6.0 5.5 2.76 0.85 0.20 0.30 0.35 0.03 0.27 0.10 0.25 0.15 — 0.05 0.06 0.05 100.00

Ingredient Corn Soybean meal (48%) Poultry meal (60%) Poultry fat Dicalcium P (18.5%) Limestone Choline chloride (60%) l-Lys (HCl) Alimet l-Thr Salt Vitamin premix3 Mineral premix4 NaSeO3 premix5 Mintrex-PSe6 HyD7 Copper sulfate Coban-608 Total Calculated analysis ME, kcal/kg CP, % Lys, % Met, % Met + Cys, % Thr, % Ca, % Nonphytate P, % Na, % Na + K − Cl, mEq/kg Added Zn, mg/kg Added Mn, mg/kg Added Cu, mg/kg Added Se, mg/kg 1

3,200 25.5 1.65 0.72 1.10 1.00 1.30 0.75 0.18 220 150 150 145 0.3

3,200 25.5 1.65 0.72 1.10 1.00 1.30 0.75 0.18 220 150 150 145 0.3

Grower II2 4

1

2

3

4

(% of diet) 46.7 51.8 51.9 51.7 51.8 36.6 32.9 32.9 32.9 32.9 6.0 6.0 6.0 6.0 6.0 5.5 4.7 4.7 4.8 4.7 2.76 2.53 2.52 2.52 2.52 0.85 0.68 0.75 0.68 0.75 0.20 0.16 0.16 0.16 0.16 0.30 0.18 0.18 0.18 0.18 0.30 0.34 0.29 0.34 0.29 0.03 — — — — 0.27 0.28 0.28 0.28 0.28 0.10 0.08 0.08 0.08 0.08 0.18 0.20 0.13 0.20 0.13 — 0.15 — 0.15 — 0.10 — 0.10 — 0.10 0.05 — — 0.05 0.05 0.05 0.06 0.05 0.06 0.05 0.05 — — — — 100.00 100.00 100.00 100.00 100.00 3,200 3,200 3,200 3,200 3,200 3,200 25.5 25.5 23.9 24.0 23.9 24.0 1.65 1.65 1.45 1.45 1.45 1.45 0.72 0.72 0.68 0.68 0.68 0.68 1.10 1.10 1.05 1.05 1.05 1.05 1.00 1.00 0.92 0.92 0.92 0.92 1.30 1.30 1.20 1.20 1.20 1.20 0.75 0.75 0.70 0.70 0.70 0.70 0.18 0.18 0.18 0.18 0.18 0.18 220 220 213 213 213 213 150 150 120 120 120 120 150 150 120 120 120 120 145 145 145 145 145 145 0.3 0.3 0.3 0.3 0.3 0.3

Feed offered to toms from 42 to 56 d of age at 3.5 kg/bird in the form of pellets. Feed offered to toms from 56 to 70 d of age at 4.0 kg/bird in the form of pellets. 3 Each kilogram of vitamin premix (0.1% inclusion) supplied the following per kilogram of complete feed: vitamin A, 13,200 IU; cholecalciferol, 4,000 IU; α-tocopherol, 66 IU; niacin, 110 mg; pantothenic acid, 22 mg; riboflavin, 13.2 mg; pyridoxine, 8 mg; menadione, 4 mg; folic acid, 2.2 mg; thiamin, 4 mg; biotin, 0.253 mg; vitamin B12, 0.04 mg; ethoxyquin, 100 mg. 4 Each kilogram of mineral premix (0.1% inclusion) supplied the following per kilogram of complete feed: 60 mg of Zn as ZnSO4·H2O, 60 mg of Mn as MnSO4·H2O, 40 mg of Fe as FeSO4·H2O, 5 mg of Cu as CuSO4, 1.25 mg of I as Ca(IO3)2, 1 mg Co as CoSO4. 5 NaSeO3 premix provided 0.3 mg of Se/kg of complete feed. 6 Mintrex PSe provided the following per kilogram of complete feed: 40 mg of Zn, 40 mg of Mn, 20 mg of Cu, and 0.3 mg of Se (as Se yeast). To compensate for the lower I contribution from the mineral premix inclusion, 1.3 g of Ca(IO3)2 was added per kilogram of complete feed. Mintrex PSe is a registered trademark of Novus International Inc. (St. Charles, MO). 7 HyD is a registered trademark of DSM Animal Nutrition Inc. (Parsippany, NJ). 8 Monensin. Elanco Animal Health division of Eli Lilly and Co. (Indianapolis, IN). 2

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in commercial field conditions. This aggressive growth performance satisfied our goal to maximize the chances of observing increased incidence of leg abnormalities associated with rapid growth rate. Several researchers have demonstrated that high early growth rate in turkeys is associated with increased incidence of leg abnormalities and resulting mortality (Ferket and Sell, 1989; Clarke et al., 1993). Growth-related leg problems were certainly observed in the current study as discussed below. Despite the lack of treatment effect on BW, significant treatment effects on FCR were observed throughout the experiment (Table 6). A significant HyD × MIN interaction effect was observed on mortality-adjusted FCR during the brooding phase (0 to 6 wk of age).

Among poults fed both HyD and MIN, FCR was significantly improved as compared with poults that were only fed HyD. Subsequently, cumulative FCR through 12, 17, and 20 wk of age were significantly decreased by MIN, regardless of the dietary supplementation of HyD. By 20 wk of age, cumulative FCR of the birds fed diets containing MIN was 8 points lower than controls (2.80 vs. 2.72, P < 0.01). Cumulative mortality rates through 3, 6, 10, and 20 wk of age are presented in Table 7. During the first 3 wk after placement, mortality was greater among birds fed the MIN-supplemented diets. During this early period, the poults suffered an enteric viral challenge that could not be identified, but postmortem examination of affected birds revealed significant enteric inflammation.

Table 3. Experimental diets fed to turkeys from 10 to 14 wk of age, treatments 1, 2, 3, and 4 Developer I1 Item

1

2

3

Ingredient Corn Soybean meal (48%) Poultry meal (60%) Poultry fat Dicalcium P (18.5%) Limestone Choline chloride (60%) l-Lys (HCl) Alimet l-Thr Salt Vitamin premix3 Mineral premix4 NaSeO3 premix5 Mintrex-PSe6 HyD7 Copper sulfate Total Calculated analysis ME, kcal/kg CP, % Lys, % Met, % Met + Cys, % Thr, % Ca, % Nonphytate P, % Na, % Na + K − Cl, mEq/kg Added Zn, mg/kg Added Mn, mg/kg Added Cu, mg/kg Added Se, mg/kg 1

54.0 29.9 5.6 6.1 2.33 0.73 0.13 0.17 0.27 — 0.29 0.08 0.20 0.15 — — 0.06 100.00

54.1 29.9 5.6 6.1 2.33 0.78 0.13 0.17 0.22 — 0.29 0.08 0.13 — 0.10 — 0.05 100.00

54.0 29.9 5.7 6.1 2.33 0.72 0.13 0.17 0.27 — 0.29 0.08 0.20 0.15 — 0.05 0.06 100.00

3,300 22.4 1.35 0.60 0.95 0.85 1.15 0.65 0.18 200 120 120 145 0.3

3,300 22.4 1.35 0.60 0.95 0.85 1.15 0.65 0.18 200 120 120 145 0.3

3,300 22.4 1.35 0.60 0.95 0.85 1.15 0.65 0.18 200 120 120 145 0.3

Developer II2 4

1

(% of diet) 54.1 59.4 29.9 25.1 5.6 5.0 6.1 6.2 2.32 2.17 0.78 0.77 0.13 0.06 0.17 0.18 0.22 0.28 — 0.04 0.29 0.30 0.08 0.08 0.13 0.20 — 0.15 0.10 — 0.05 — 0.05 0.06 100.00 100.00 3,300 22.4 1.35 0.60 0.95 0.85 1.15 0.65 0.18 200 120 120 145 0.3

3,350 20.0 1.20 0.58 0.90 0.80 1.10 0.60 0.18 180 120 120 145 0.3

2

3

4

59.6 25.2 5.0 6.2 2.17 0.83 0.06 0.18 0.23 0.04 0.30 0.08 0.13 — 0.10 —

59.4 25.1 5.0 6.2 2.17 0.77 0.06 0.18 0.28 0.04 0.30 0.08 0.20 0.15 — 0.05

59.4 25.2 5.0 6.2 2.17 0.84 0.06 0.18 0.23 0.04 0.30 0.08 0.13 — 0.10 0.05

0.05 100.00

3,350 20.0 1.20 0.58 0.90 0.80 1.10 0.60 0.18 180 120 120 145 0.3

0.06 100.00

3,350 20.0 1.20 0.58 0.90 0.80 1.10 0.60 0.18 180 120 120 145 0.3

0.05 100.00

3,350 20.0 1.20 0.58 0.90 0.80 1.10 0.60 0.18 180 120 120 145 0.3

Feed offered to toms from 70 to 84 d of age at 6.0 kg/bird in the form of pellets. Feed offered to toms from 84 to 98 d of age at 7.0 kg/bird in the form of pellets. 3 Each kilogram of vitamin premix (0.1% inclusion) supplied the following per kilogram of complete feed: vitamin A, 13,200 IU; cholecalciferol, 4,000 IU; α-tocopherol, 66 IU; niacin, 110 mg; pantothenic acid, 22 mg; riboflavin, 13.2 mg; pyridoxine, 8 mg; menadione, 4 mg; folic acid, 2.2 mg; thiamin, 4 mg; biotin, 0.253 mg; vitamin B12, 0.04 mg; ethoxyquin, 100 mg. 4 Each kilogram of mineral premix (0.1% inclusion) supplied the following per kilogram of complete feed: 60 mg of Zn as ZnSO4·H2O, 60 mg of Mn as MnSO4·H2O, 40 mg of Fe as FeSO4·H2O, 5 mg of Cu as CuSO4, 1.25 mg of I as Ca(IO3)2, 1 mg of Co as CoSO4. 5 NaSeO3 premix provided 0.3 mg of Se/kg of complete feed. 6 Mintrex PSe provided the following per kilogram of complete feed: 40 mg of Zn, 40 mg of Mn, 20 mg of Cu, and 0.3 mg of Se (as Se yeast). To compensate for the lower I contribution from the mineral premix inclusion, 1.3 g of Ca(IO3)2 was added per kilogram of complete feed. Mintrex PSe is a registered trademark of Novus International Inc. (St. Charles, MO). 7 HyD is a registered trademark of DSM Animal Nutrition Inc. (Parsippany, NJ). 2

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Table 4. Experimental diets fed to turkeys from 14 to 20 wk of age, treatments 1, 2, 3, and 4 Prefinisher1 Item

1

2

Finisher2 3

Ingredient Corn Soybean meal (48%) Poultry meal (60%) Poultry fat Dicalcium P (18.5%) Limestone Choline chloride (60%) l-Lys (HCl) Alimet l-Thr Salt Vitamin premix3 Mineral premix4 NaSeO3 premix5 Mintrex-PSe6 HyD7 Copper sulfate Total Calculated analysis ME, kcal/kg CP, % Lys, % Met, % Met + Cys, % Thr, % Ca, % Nonphytate P, % Na, % Na + K − Cl, mEq/kg Added Zn, mg/kg Added Mn, mg/kg Added Cu, mg/kg Added Se, mg/kg

64.0 22.8 3.0 6.1 2.10 0.85 0.04 0.15 0.23 0.02 0.33 0.05 0.15 0.15 — — 0.06 100.00

64.3 22.8 2.9 6.0 2.10 0.90 0.04 0.15 0.18 0.02 0.33 0.05 0.08 — 0.10 — 0.05 100.00

64.0 22.8 3.0 6.1 2.10 0.85 0.04 0.15 0.23 0.02 0.33 0.05 0.15 0.15 — 0.05 0.06 100.00

3,360 18.0 1.05 0.50 0.80 0.70 1.00 0.55 0.18 170 90 90 145 0.3

3,360 18.0 1.05 0.50 0.80 0.70 1.00 0.55 0.18 170 90 90 145 0.3

3,360 18.0 1.05 0.50 0.80 0.70 1.00 0.55 0.18 170 90 90 145 0.3

4

1

(% of diet) 64.3 67.7 22.8 20.5 2.9 2.3 6.0 6.1 2.10 1.65 0.90 0.75 0.04 0.05 0.15 0.13 0.18 0.15 0.02 — 0.33 0.34 0.05 0.05 0.08 0.15 — 0.15 0.1 — 0.05 — 0.05 0.06 100.00 100.00 3,360 18.0 1.05 0.50 0.80 0.70 1.00 0.55 0.18 170 90 90 145 0.3

3,360 16.7 0.95 0.41 0.70 0.63 0.85 0.45 0.18 160 90 90 145 0.3

2

3

4

67.9 20.5 2.3 6.0 1.65 0.85 0.05 0.13 0.10 — 0.34 0.05 0.08 — 0.10 — 0.05 100.00

67.6 20.5 2.3 6.1 1.65 0.75 0.05 0.13 0.15 — 0.34 0.05 0.15 0.15 — 0.05 0.06 100.00

67.8 20.5 2.3 6.0 1.65 0.85 0.05 0.13 0.10 — 0.34 0.05 0.08 — 0.1 0.05 0.05 100.00

3,360 16.7 0.95 0.41 0.70 0.63 0.85 0.45 0.18 160 90 90 145 0.3

3,360 16.7 0.95 0.41 0.70 0.63 0.85 0.45 0.18 160 90 90 145 0.3

3,360 16.7 0.95 0.41 0.70 0.63 0.85 0.45 0.18 160 90 90 145 0.3

1

Feed offered to toms from 98 to 119 d of age at 10.0 kg/bird in the form of pellets. Feed offered to toms from 119 to 140 d of age at 12.0 kg/bird in the form of pellets. 3 Each kilogram of vitamin premix (0.1% inclusion) supplied the following per kilogram of complete feed: vitamin A, 13,200 IU; cholecalciferol, 4,000 IU; α-tocopherol, 66 IU; niacin, 110 mg; pantothenic acid, 22 mg; riboflavin, 13.2 mg; pyridoxine, 8 mg; menadione, 4 mg; folic acid, 2.2 mg; thiamin, 4 mg; biotin, 0.253 mg; vitamin B12, 0.04 mg; ethoxyquin, 100 mg. 4 Each kilogram of mineral premix (0.1% inclusion) supplied the following per kilogram of complete feed: 60 mg of Zn as ZnSO4·H2O, 60 mg of Mn as MnSO4·H2O, 40 mg of Fe as FeSO4·H2O, 5 mg of Cu as CuSO4, 1.25 mg of I as Ca(IO3)2, 1 mg of Co as CoSO4. 5 NaSeO3 premix provided 0.3 mg of Se/kg of complete feed. 6 Mintrex PSe provided the following per kilogram of complete feed: 40 mg of Zn, 40 mg of Mn, 20 mg of Cu, and 0.3 mg of Se (as Se yeast). To compensate for the lower I contribution from the mineral premix inclusion, 1.3 g of Ca(IO3)2 was added per kilogram of complete feed. Mintrex PSe is a registered trademark of Novus International Inc. (St. Charles, MO). 7 HyD is a registered trademark of DSM Animal Nutrition Inc. (Parsippany, NJ). 2

However, after 6 wk of age, there was no effect of MIN on cumulative mortality. By 10 wk of age, dietary HyD significantly decreased cumulative mortality rate (11.4 vs. 7.2%, P < 0.05). By 20 wk of age, however, cumulative mortality was marginally decreased by dietary MIN supplementation (18.5 vs. 15.6%, P = 0.085) and marginally increased by dietary HyD supplementation (16.9 vs. 17.1%, P = 0.072). Regardless of treatment, most of the mortalities observed after 10 wk of age were birds lost to leg problems or sudden death by aortic rupture. Of the 4 birds that died from spiral femur fractures between 15 and 18 wk of age, none were among the birds fed diets supplemented with MIN. Similarly, none of the birds that died of aortic rupture consumed feed supplemented with MIN.

Leg Abnormalities The incidence of leg abnormalities evaluated by walking ability at 12, 15, 17, and 20 wk of age is summarized in Tables 8, 9, 10, and 11, respectively. There were no treatment effects observed on the incidence of valgus or varus leg deformations at 12 wk of age; however, the incidence of birds exhibiting shaky leg was significantly lower among birds fed diets supplemented with MIN than those fed diets containing only inorganic trace minerals (11.5 vs. 4.2%, P = 0.001). The incidence of total leg problems was also markedly decreased by dietary MIN supplementation (16.0 vs. 7.1%, P = 0.001). At 15 wk of age (Table 9), birds fed diets supplemented with MIN had a much lower incidence of mild valgus

125

ORGANIC TRACE MINERALS AND VITAMIN D IN TURKEY DIETS Table 5. Effect of dietary supplementation of 25-hydroxycholecalciferol (HyD) and organic trace minerals (MIN) on BW of Nicholas 85X700 turkeys1 Week of age HyD2

MIN3

− − − + + − + + SEM(41)4 Source of variation HyD MIN HyD × MIN

6

12

2.75 2.72 2.72 2.77 0.014

10.43 10.50 10.50 10.63 0.039

0.698 0.678 0.170

0.209 0.203 0.693

15 (kg) 14.60 14.81 14.81 14.90 0.064 (P-value) 0.238 0.231 0.617

17

20

17.26 17.65 17.55 17.63 0.082

20.70 21.26 21.21 21.23 0.010

0.405 0.157 0.359

0.232 0.147 0.182

1

Values are mean of 12 replicate pens of about 15 birds per pen. HyD-supplemented diet contained 92 μg of 25-hydroxycholecalciferol per kilogram of feed. 3 Mintrex PSe provided the following per kilogram of complete feed: 40 mg of Zn, 40 mg of Mn, and 20 mg of Cu as a complex with Met-hydroxy analog and 0.3 mg of Se from Se-enriched yeast. 4 SEM(41) = pooled SEM with 41 df. 2

deformation than controls (19.5 vs. 3.7%, P = 0.0001), and they had a lower incidence of shaky leg (P < 0.05) and total leg problems (30.1 vs. 8.6%, P = 0.0001), similar to the observations at 12 wk of age (Table 8). There were no treatment effects on the incidence of leg problems that severely impeded mobility at 15 wk of age. Considering all leg problems at 15 wk of age, the benefit of MIN was less pronounced among turkeys fed the HyD-supplemented diets. The treatment effects observed at 15 wk of age (Table 9) were also observed at 17 wk of age (Table 10). In addition to decreasing the incidence of total valgus deformations (P = 0.0001), MIN significantly decreased the incidence of total varus deformities (P < 0.05). Moreover, MIN clearly decreased the incidence of shaky leg at 17 wk of age (13 vs. 2.1%, P = 0.0001). The MIN-supplemented birds

were more willing to walk than were the birds in the other treatment groups. Furthermore, MIN decreased the incidence of total leg problems (P < 0.0001). By 20 wk of age, dietary MIN decreased the incidence of total valgus (P < 0.05) and total leg problems (P < 0.01), whereas dietary HyD apparently increased total leg problems (P = 0.05; Table 11). Dietary HyD increased the incidence of valgus deformations (P < 0.05).

Mechanical Fracture Resistance Testing of Tibia and Femur Bones Bone strength has been primarily associated with adequate formation and maintenance of bone organic matrix, collagen crosslinking, collagen fiber orientation,

Table 6. Effect of dietary supplementation of 25-hydroxycholecalciferol (HyD) and organic trace minerals (MIN) on feed conversion ratio of Nicholas 85X700 turkeys1 Week of age HyD2

MIN3


0 to 6

1.415b 1.428ab 1.432a 1.416b 0.003 0.734 0.846 0.034

0 to 12 (g of feed/g of BW 2.05 2.01 2.05 1.97 0.011 (P-value) 0.383 0.014 0.403

0 to 17

0 to 20

gain) 2.58 2.53 2.61 2.55 0.012

2.78 2.74 2.82 2.70 0.015

0.563 0.012 0.342

0.898 0.009 0.211

a,b Means with different superscripts within a column differ significantly (P ≤ 0.05) based on factorial source of variation analysis of arcsine√ percentage-transformed data. 1 Values are mean of 12 replicate pens of about 15 birds per pen, after adjusting for mortality. 2 HyD-supplemented diet contained 92 μg of 25-hydroxycholecalciferol per kilogram of feed. 3 Mintrex PSe provided the following per kilogram of complete feed: 40 mg of Zn, 40 mg of Mn, and 20 mg of Cu as a complex with Met-hydroxy analog and 0.3 mg of Se from Se-enriched yeast. 4 SEM(41) = pooled SEM with 41 df.

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Ferket et al. Table 7. Effect of dietary supplementation of 25-hydroxycholecalciferol (HyD) and organic trace minerals (MIN) on mortality rate of Nicholas 85X700 turkeys1 Week of age HyD2

MIN3

0 to 3


0 to 6

0 to10

0 to 20

(% of total birds placed) 3.8 10.7 11.0 12.0 5.3 7.7 5.8 6.7 0.75 0.86 (P-value) 0.167 0.038 0.753 0.121 0.192 0.126

1.0 7.7 2.9 4.8 0.59 0.878 0.001 0.058

16.0 17.8 20.7 13.5 0.13 0.072 0.085 0.214

1

Values are mean of 12 replicate pens of about 15 birds per pen. HyD-supplemented diet contained 92 μg of 25-hydroxycholecalciferol per kilogram of feed. 3 Mintrex PSe provided the following per kilogram of complete feed: 40 mg of Zn, 40 mg of Mn, and 20 mg of Cu as a complex with Met-hydroxy analog and 0.3 mg of Se from Se-enriched yeast. 4 SEM(41) = pooled SEM with 41 df. 2

and bone modeling and remodeling rather than bone mineralization (Rath et al., 1999, 2000). To better understand the treatment effects on bone development and strength, it is important to evaluate several parameters of bone biomechanics and not just mineralization (Oviedo-Rondón et al., 2006a). Resistance to breaking in a 3- or 4-point bending assay has long been a marker for bone strength and measures primarily strength conferred by the collagen matrix (Rath et al., 1999, 2000). The spontaneous spiral femoral fractures that occur in the field can be replicated in the laboratory using torsion tests (Crespo et al., 2000; Oviedo-Rondón et al., 2006c). Therefore, the biomechanical properties of tibia and femur bones were evaluated by bending (Table 12) and

torsion (Table 13) tests, respectively. No significant interaction effects were observed in cortical thickness of bones (t). However, cortical thickness was greater among the MIN-treated birds than the controls (2.21 vs. 1.88 mm, P = 0.001) at site of failure after the 4-point bending tests on the tibiotarsus, but not in torsional tests (P > 0.05) on the femur. The maximum applied moment (M) and the resulting bending stress required for tibia bones to break (σmax) in the 4-point bending tests was greater among the MIN supplementation birds than controls (28.6 vs. 25.8 Nm, P < 0.01; and 121.8 vs. 112.6 MPa, P < 0.05, respectively), especially when both MIN and HyD were added to the diet (P = 0.05; Table 12). The average maximum shear stress (τmax) at failure of femoral bones was increased

Table 8. Effects of dietary supplementation of 25-hydroxycholecalciferol (HyD) and organic trace minerals (MIN) on the incidence and severity of leg abnormalities among Nicholas 85X700 turkeys at 12 wk of age Valgus1 HyD

MIN

− − − + + − + + SEM(41)4 Source of variation HyD MIN HyD × MIN a–c

Varus1

1

2

3

Total

5.3 1.8 2.6 3.1 1.54

0.0 0.6 0.5 0.0 0.38

0.0 0.0 0.0 0.0 —

5.3 2.4 3.1 3.1 1.55

0.961 0.594 0.210

0.982 0.982 0.164

— — —

0.968 0.607 0.448

1

2

(%) 0.0 0.0 0.0 0.0 0.6 0.0 0.0 0.0 0.28 — (P-value) 0.323 — 0.323 — 0.323 —

3

Total

SL2

Total LP3

0.0 0.0 0.0 0.0 —

0.0 0.0 0.6 0.0 0.28

12.8a 4.2c 10.1ab 4.3bc 2.55

18.2a 6.7c 13.8ab 7.4bc 2.76

— — —

0.323 0.323 0.323

0.899 0.001 0.452

0.994 0.001 0.173

Means with different superscripts within a column differ significantly (P ≤ 0.05) based on treatment source of variation analysis of arcsine√ percentage-transformed data. 1 Valgus and varus leg abnormality severity reported as walking ability scores: 1 = mobile with mild limp; 2 = resistant mobility with significant limp; and 3 = down and crippled. 2 SL = shaky leg. 3 Total leg problems (LP) = percentage of all the birds with leg problems including valgus, varus, and shaky legs. 4 SEM(41) = pooled SEM with 41 df.

127



MIN


1

19.1a 1.9b 20.0a 5.4b 2.62 0.082 0.0001 0.413

Varus1

2

3

1.2 0.0 1.2 0.6 0.65

0.0 0.0 0.0 0.0 —

0.635 0.168 0.660

— — —

Total

20.3a 1.9c 21.2a 6.0b 2.75 0.051 0.0001 0.304

1 (%) 1.8 1.8 2.4 1.2 1.12 (P-value) 0.997 0.541 0.809

2

3

Total

SL2

Total LP3

0.0 0.6 1.2 0.6 0.59

0.6 0.0 0.6 0.6 0.53

2.4 2.4 4.2 2.5 1.29

7.9 1.3 4.2 3.1 1.58

30.5a 5.5c 29.6a 11.6b 2.24

0.307 0.984 0.326

0.557 0.587 0.557

0.506 0.533 0.762

0.995 0.033 0.139

0.020 0.0001 0.010

a–c Means with different superscripts within a column differ significantly (P ≤ 0.05) based on factorial source of variation analysis of arcsine√ percentage-transformed data. 1 Valgus and varus leg abnormality severity reported as walking ability scores: 1 = mobile with mild limp; 2 = resistant mobility with significant limp; and 3 = down and crippled. 2 SL = shaky leg. 3 Total leg problems (LP) = percentage of all the birds with leg problems including valgus, varus, and shaky legs. 4 SEM(41) = pooled SEM with 41 df.

(P < 0.05) by the dietary supplementation of both MIN and HyD (Table 13). Therefore, dietary MIN and HyD increased the biomechanical strength of tibias and femurs in 17-wk-old turkey toms. Treatments evaluated in the present experiment had significant effects on average shear stress of femur and cortical thickness at the site of failure of tibias measured after bending tests. The tibias from turkeys fed diets supplemented with MIN had consistently thicker cortical areas. However, the femoral cortical thicknesses measured after torsion tests were not affected by treatments. The effects of dietary MIN supplementation observed on the biomechanical properties of tur-

key femurs and tibias agree with the observations and conclusions of Cubo and Casinos (1998, 2000). These researchers reported that avian bones endure different stresses during locomotion. Although the tibiotarsus is subjected primarily to longitudinal stresses caused by compression, tension, or bending loads, the femur may also be subjected to torsional loading. The laminar microstructure of the bone tissue in the femur, as well as the relatively large diameters and thin-wall cross sections, is characteristic of a bone subjected to torsional loading. If the femur is optimizing its structure to better resist torsional loading, it may increase its diameter not necessarily its thickness. In contrast, it is possible


MIN


1

19.1a 3.2b 16.1a 3.6b 2.24 0.650 0.0001 0.249

Varus1

2

3

1.8 0.6 3.8 0.6 1.10

0.6 0.0 1.2 0.6 0.57

0.520 0.057 0.504

0.316 0.299 0.986

Total

21.5a 3.9b 21.2a 4.8b 2.76 0.651 0.0001 0.439

1 (%) 1.2 0.6 1.8 0.0 0.69 (P-value) 0.987 0.087 0.382

2

3

Total

0.6 0.0 0.0 0.0 0.30

0.0 0.0 0.0 0.0 —

1.8 0.6 1.8 0.0 0.73

0.323 0.323 0.323

— — —

0.696 0.045 0.673

SL2

14.2a 0.6b 11.7a 3.6b 2.28 0.515 0.0001 0.286

Total LP3

37.5a 5.1b 34.7a 8.4b 3.27 0.528 0.0001 0.171

a,b Means with different superscripts within a column differ significantly (P ≤ 0.05) based on treatment source of variation analysis of arcsine√ percentage-transformed data. 1 Valgus and varus leg abnormality severity reported as walking ability scores: 1 = mobile with mild limp; 2 = resistant mobility with significant limp; and 3 = down and crippled. 2 SL = shaky leg. 3 Total leg problems (LP) = percentage of all the birds with leg problems including valgus, varus, and shaky legs. 4 SEM(41) = pooled SEM with 41 df.

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Ferket et al.


MIN


Varus1

1

2

3

Total

8.2b 6.2b 17.1a 9.9ab 2.12

5.1 3.2 7.0 3.0 1.62

0.8b 0.0b 0.0b 4.0a 0.80

14.1ab 9.4b 24.1a 16.9ab 2.87

0.676 0.107 0.638

0.055 0.055 0.005

0.015 0.049 0.570

0.017 0.037 0.851

1

2

(%) 2.1 0.0 0.0 0.9 0.0 0.0 0.0 1.5 0.75 0.64 (P-value) 0.153 0.594 0.153 0.082 0.153 0.594

3

Total

SL2

Total LP3

0.0 0.0 0.0 0.0 —

2.1 0.8 0.0 1.5 0.99

5.6 3.9 5.6 3.1 1.84

21.7ab 14.1b 29.7a 21.4ab 2.96

— — —

0.543 0.772 0.171

0.791 0.195 0.810

0.054 0.008 0.984

a,b Means with different superscripts within a column differ significantly (P ≤ 0.05) based on factorial source of variation analysis of arcsine√ percentage-transformed data. 1 Valgus and varus leg abnormality severity reported as walking ability scores: 1 = mobile with mild limp; 2 = limited mobility with significant limp; and 3 = down and crippled. 2 SL = shaky leg. 3 Total leg problems (LP) = percentage of all the birds with leg problems including valgus, varus, and shaky legs. 4 SEM(41) = pooled SEM with 41 df.

to observe increased cortical thickness in tibias that optimize their shape for bending stresses (Turner and Burr, 2001). Significant treatment interaction effects were observed for both mechanical tests. Dietary supplementation of both HyD and MIN resulted in greater values for applied moment and stress at breakage in tibias, and maximum shear of stress at failure in femurs. Synergistic effects of vitamin D and trace minerals have been observed by other researchers. Yamaguchi and Oishi (1989) demonstrated that Zn enhances the ability of 1,25-dihydroxycholecalciferol to increase the activity of bone alkaline phosphatase, an enzyme that is associated with proper bone mineralization. Different sources

of vitamin D also enhance the utilization of Cu (Aoyagi and Baker, 1995) and Mn (Biehl et al., 1995). The effect of organic trace minerals on the torsion test results observed in this study with turkeys are consistent with those observed in broilers (Rucker et al., 1975; Opsahl et al., 1982). None of the diets formulated for this experiment were deficient in any trace mineral, because optimum growth rates were obtained. However, there is evidence that trace mineral requirements for optimal bone development may be greater than for fast growth rates (Dibner and Richards, 2006; OviedoRondón et al., 2006b). The MIN product used in this experiment contained chelated Zn, Mn, and Cu and organic Se. Zinc plays important roles in collagen syn-

Table 12. Effect of dietary supplementation of 25-hydroxycholecalciferol (HyD) and organic trace minerals (MIN) on tibia biomechanical properties of 17-wk-old Nicholas 85X700 turkeys in a 4-point bending test HyD

MIN

− − − + + − + + SEM(41)7 Source of variation HyD MIN HyD × MIN a,b

t1 (mm)

Major axis diameter2 (mm)

1.9 2.1 1.9 2.3 0.09

18.0 18.3 18.5 18.2 0.27

0.166 0.001 0.286

0.386 0.955 0.300

Minor axis diameter3 (mm) 13.3 13.2 13.2 13.1 0.21 (P-value) 0.539 0.659 0.976

Ix4 (m4) ×10−9

M5 (Nm)

σmax6 (MPa)

1.5 1.5 1.5 1.6 0.07

25.8b 26.7ab 24.7b 30.5a 1.19

112.6b 114.5ab 107.4b 129.1a 4.96

0.950 0.756 0.986

0.276 0.008 0.047

0.347 0.022 0.051

Means with different superscripts within a column differ significantly (P ≤ 0.05) based on treatment source of variation analysis. t = average thickness of each bone measured on the frontal, caudal, medial, and lateral sides of the bone above and below the break. 2 Major axis diameter = bone diameter measured from the medial to lateral sides of the bone at the thinnest point on the bone, 3/4 of the distance from the top to the bottom of the bone. 3 Minor axis diameter = bone diameter measured from the frontal to caudal sides of the bone at the same point. 4 Ix = area moment of inertia of the bone using the formula for an ellipse. 5 M = applied moment. 6 σmax = maximum normal stress at breakage. 7 SEM(41) = pooled SEM with 41 df. 1

129


Table 13. Effect of dietary supplementation of 25-hydroxycholecalciferol (HyD) and organic trace minerals (MIN) on femur biomechanical properties of 17-wk-old Nicholas 85X700 turkeys in a torsion test t1 (mm)

Major axis diameter2 (mm)

Minor axis diameter3 (mm)

− − − + + − + + SEM(41)8 Source of variation

1.88 1.95 2.04 1.95 0.10

18.54 18.44 18.31 18.08 0.33

17.18 17.20 17.21 16.76 0.23

HyD MIN HyD × MIN

0.469 0.951 0.462

HyD

MIN

0.386 0.618 0.848

0.383 0.354 0.322

Q4 (m3) ×10−7 6.41 6.56 6.81 6.14 0.34 (P-value) 0.987 0.453 0.244

Torquemax5 (Nm)

τmax6 (MPa)

29.34 26.73 27.30 28.92 1.13

45.52b 41.51b 45.32ab 50.75a 2.7

0.949 0.669 0.074

0.300 0.784 0.037

Anglemax7 22.3 19.8 20.8 21.4 1.3 0.999 0.491 0.255

a,b

Means with different superscripts within a column differ significantly (P ≤ 0.05) based on treatment source of variation analysis. t = average thickness of the bone measured on the frontal, medial, caudal, and lateral sides of the bone for the top and bottom portions of the bone after breaking. 2 Major axis diameter = medial-lateral diameter. 3 Minor axis diameter = frontal-caudal diameter. 4 Q = geometry parameter relating the applied torque to the resulting shear stress, calculated assuming a hollow ellipse with inside and outside boundaries represented by similar ellipses. 5 Torquemax = maximum torque measured during the test. 6 τmax = maximum shear stress at failure assuming the inside and outside boundaries of the bone are similar ellipses with an assumed thickness of t − (the average distance between the 2 ellipses). 7 Anglemax = rotation in the bone at failure. 8 SEM(41) = pooled SEM with 41 df. 1

thesis and turnover in developing bone, as well as in the regulation of hydroxyapaptite crystallization (Starcher et al., 1980; Wu et al., 1993; Sauer et al., 1997; Nie et al., 1998; Orth, 1999; Wu et al., 2002). Furthermore, gene knockout studies in mice have shown that the Znfinger transcription factor Gli2 is required for normal endochondral ossification to occur (Miao et al., 2004). Although Zn promotes collagen synthesis and turnover, the collagen and elastin matrices must be stabilized by crosslinking for proper development and to confer tensile strength and elasticity to the bone (Carlton and Henderson, 1964; Opsahl et al., 1982; Rucker et al., 1998; Rath et al., 1999, 2000). This crosslinking is accomplished by the cuproenzyme lysyl oxidase (Opsahl et al., 1982; Rucker et al., 1998). Indeed, bone fragility in response to Cu deficiency in many animal species has been reported as early as the 1940s (Bennett et al., 1948; Tinker and Rucker, 1985), and fractures in femoral bones are frequently associated with decreased serum and bone Cu in several species, including humans (Beattle and Avenell, 1992). Adequate Cu intake is more critical for acquisition of peak bone mass in long bones, whereas adequate and balanced intakes of both Cu and Zn may be more critical for an optimal bone mass in the trabecular bones (Roughead and Lukaski, 2003). Manganese is a cofactor for the glycosyltransferases that are required for the formation of the mucopolysaccharides that form the hyaline cartilage of immature bone, which are essential for proper development (Fawcett, 1994; Gilbert, 1997; Underwood and Suttle, 1999). Manganese deficiency in poultry species can cause twisting and bending of the tibia, enlargement and malformation of the tibiometatarsal joint,

shortening and thickening of long bones, and slipping of the gastrocnemius tendon from its condyles (Underwood and Suttle, 1999). Selenoproteins are involved in bone metabolism and ossification as well (Beattle and Avenell, 1992; Oviedo-Rondón et al., 2006b). In a study of Se deficiency in rats over 2 generations, the deficient rats exhibited multiple signs of abnormal bone development, including a highly significant reduction in bone mineral density (Moreno-Reyes et al., 2001). Trace minerals are also important to maintain several functions of bone, cartilage, and tendons during daily physical activities (Opsahl et al., 1982; Moreno-Reyes et al., 2001; Speich et al., 2001), especially in fast-growing animals (Beattle and Avenell, 1992). These functions of trace minerals may explain why dietary MIN inclusion decreased the incidence of varus, valgus, or shaky leg abnormalities in the current experiment. The complete etiology of these leg disorders is not well understood, but several authors suggested that trace minerals may decrease their incidence (Beattle and Avenell, 1992; Lilburn, 1994; Julian, 1998). In conclusion, dietary supplementation of organic trace minerals (Zn, Mn, and Cu) as complexed with methionine hydroxy analog along with Se yeast (Mintrex PSe) can decrease the incidence of leg abnormalities (varus, valgus, and shaky leg) associated with rapid growth. Furthermore, dietary MIN supplementation can improve long bone strength, especially when combined with dietary HyD supplementation. Increased bone strength will likely contribute to fewer broken bones in commercial turkey production. Therefore, the dividends associated with decreased leg abnormalities and a reduction in broken leg bones in the MIN-sup-

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plemented birds include improved animal welfare and FCR during the growing and finishing period of turkey toms.

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