North American Journal of Aquaculture Growth ...

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Growth Performance of Hybrid Striped Bass, Rainbow Trout, and Cobia Utilizing Asian Carp Meal-Based Aquafeeds a

a

John Bowzer & Jesse Trushenski a

Center for Fisheries Aquaculture and Aquatic Sciences, Southern Illinois University Carbondale, 1125 Lincoln Drive, Carbondale, Illinois 62901, USA Published online: 16 Dec 2014.

Click for updates To cite this article: John Bowzer & Jesse Trushenski (2015) Growth Performance of Hybrid Striped Bass, Rainbow Trout, and Cobia Utilizing Asian Carp Meal-Based Aquafeeds, North American Journal of Aquaculture, 77:1, 59-67, DOI: 10.1080/15222055.2014.960117 To link to this article: http://dx.doi.org/10.1080/15222055.2014.960117

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North American Journal of Aquaculture 77:59–67, 2015 C American Fisheries Society 2015 ISSN: 1522-2055 print / 1548-8454 online DOI: 10.1080/15222055.2014.960117

ARTICLE

Growth Performance of Hybrid Striped Bass, Rainbow Trout, and Cobia Utilizing Asian Carp Meal-Based Aquafeeds John Bowzer and Jesse Trushenski*

Downloaded by [116.112.66.102] at 23:10 26 August 2015

Center for Fisheries Aquaculture and Aquatic Sciences, Southern Illinois University Carbondale, 1125 Lincoln Drive, Carbondale, Illinois 62901, USA

Abstract Fish meal sparing is more difficult for nutritionally demanding carnivorous fishes, but economic considerations and the limited supply of fish meal continue to incentivize investigations of alternative protein sources for aquafeeds. A promising alternative to traditional, marine-origin fish meal is fish meal derived from undesirable freshwater species, such as the invasive Asian carp Hypophthalmichthys spp. To assess the relative value of such ingredients, we evaluated growth performance of juvenile hybrid Striped Bass (White Bass Morone chrysops × Striped Bass M. saxatilis; initial weight, 21.9 ± 0.2 g [mean ± SE]), Rainbow Trout Oncorhynchus mykiss (15.1 ± 0.2 g), and Cobia Rachycentron canadum (57.2 ± 0.5 g) reared for 8 weeks on practical diets containing different levels of menhaden fish meal (MFM), Asian carp meal (CFM), or a 50:50 blend of these ingredients such that 0, 20, 40, or 60% of the estimated digestible protein content was derived from fish meal. Growth performance was generally consistent across taxa, and weight gain tended to increase with fish meal inclusion, regardless of its origin. However, Cobia did perform better on CFM-based diets, suggesting that MFM or CFM can yield improved performance for some taxa or life stages, but these differences are likely to be marginal in most circumstances. We conclude CFM is a suitable and perhaps lower-cost alternative to MFM in feeds for carnivorous fishes.

Feed accounts for a substantial portion of overall operating costs (40–50%) for intensive aquaculture facilities (Cheng et al. 2004). Protein is typically the most expensive component of animal feed, and this is particularly problematic in aquafeeds because fish have a much higher protein demand compared with other livestock (Keembiyehetty and Gatlin 1992). Historically, fish meal was used as a primary ingredient in aquafeeds because of its high protein density, favorable amino acid profile, and digestibility and palatability to aquatic livestock. However, fish meal inclusion rates have been declining in recent decades (Tacon and Metian 2008; Tacon et al. 2011) because it is considerably more expensive than other alternative plant- and animalderived protein sources (Gatlin et al. 2007; Welch et al. 2010; FAO 2014). However, sparing fish meal with these alternatives can be particularly difficult for nutritionally demanding carnivorous fishes, which may not readily accept or perform as well on diets with reduced levels or free of fish meal. Fish meal has

been the primary protein source for carnivorous species because it generally meets all essential amino acid requirements, is protein dense, and is highly palatable; but, due to the high cost of this ingredient and its overall high inclusion levels in the diets, there are considerable economic incentives to reduce fish meal use in aquafeeds (Watanabe 2002). A potential alternative to traditional marine-origin fish meal is a freshwater fish meal rendered from invasive species such as Silver Carp Hypophthalmichthys molitrix and Bighead Carp H. nobilis (hereafter referred to collectively as Asian carp). Asian carp have become particularly abundant in the Mississippi River basin (McClelland et al. 2012; Tsehaye et al. 2013), and since invasive species typically have adverse effects on native populations and economically important activities (Vitousek et al. 1997; Lodge et al. 2006), a variety of control and eradication strategies have been investigated and deployed. Of these, control through increased harvest pressure is a primary focus because it

*Corresponding author: [email protected] Received June 9, 2014; accepted August 13, 2014

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is currently the only viable short-term control strategy (Conover et al. 2007). Considerable fishing pressure is needed to successfully control Asian carp in this system (Tsehaye et al. 2013); thus, market research and development have been undertaken to increase the demand for Asian carp (Nelson 2013; Varble and Secchi 2013). However, since Asian carp are not a preferred food fish in the United States, industrial applications, such as rendering into protein meals for livestock feeding, are considered the most promising to incentivize harvest (Conover et al. 2007; Bowzer et al. 2013). Asian carp meal has several advantages over other alternative protein sources. Utilization of plant-origin (i.e., derivatives of oilseeds or grains) and animal-origin (i.e., by-products of livestock processing) feedstuffs in aquafeeds can be restricted by inadequate nutrient levels, digestibility, or palatability; the presence of antinutritional factors; or practical limitations to inclusion in the diet (e.g., high cost, complications related to feed manufacturing; Glencross et al. 2007). For instance, soybean meal is one of the most promising alternative protein sources (Gatlin et al. 2007), and despite its routine use in aquafeeds (Hendricks 2003) high inclusion levels can result in undesirable effects such as poor palatability (Adelizi et al. 1998), low feed conversion efficiency (Davies and Morris 1997), and gut enteritis (Heikkinen et al. 2006; Iwashita et al. 2008). Fish meals, including Asian carp meal, do not appear to present any of these challenges (Bowzer et al., in press). Furthermore, while most marine fisheries are unlikely to withstand greater fishing pressure (FAO 2012), greater harvest of Asian carp would likely improve the ecological integrity of the Mississippi River basin. Rendering Asian carp into fish meal may increase demand and associated harvest pressure on these invasive fish, but demand for Asian carp meal is dependent on the product’s quality and pricing. Current pricing estimates for Asian carp meal range from US$600–650/metric ton (P. Hitchens, Southern Illinois University Carbondale, personal communication), considerably lower than current pricing for marine-origin fish meal ($1,500– 2,000/metric ton: FAO 2014). Additionally, an industry must be established to produce the product to supply the market. Given that, development of large-scale Asian carp meal production facilities has been relatively slow due to initial high risk of investment in a new product and little information regarding its nutritional value, contaminant load, or potential volume until recently. Researchers have begun to fill in many of these data gaps such as establishing that the digestibility of Asian carp meal is comparable to that of other fish meals in aquafeeds (Bowzer et al., in press), and its practical feeding value in Largemouth Bass Micropterus salmoides feeds is similar to menhaden fish meal (Bowzer et al. 2014). As this information has become available, interest and investment in Asian carp rendering has increased; a facility specializing in Asian carp meal production recently opened in Grafton, Illinois (Moon 2014). Therefore, Asian carp meal appears to be a promising protein source for aquafeeds, but its utilization by a range of nutritionally demanding carnivorous fish species has yet to be fully determined.

Accordingly, we assessed the growth performance of hybrid Striped Bass (White Bass Morone chrysops × Striped Bass M. saxatilis), Rainbow Trout Oncorhynchus mykiss, and Cobia Rachycentron canadum fed diets containing different levels of menhaden fish meal (MFM) or Asian carp meal (CFM).

METHODS Fish were held in recirculating aquaculture systems with continuous aeration and mechanical and biological filtration units. Trials with hybrid Striped Bass (initial weight, 21.9 ± 0.2 g [mean ± SE]; Keo Fish Farms, Keo, Arkansas) and Rainbow Trout (15.1 ± 0.2 g; Crystal Lake Fisheries, Ava, Missouri) were conducted at the Center for Fisheries, Aquaculture, and Aquatic Sciences (CFAAS) at Southern Illinois University Carbondale, Carbondale, Illinois, while the Cobia (57.2 ± 0.5 g; Troutlodge Marine Farms, Vero Beach, Florida) trial was conducted at the Virginia Seafood Agricultural Research and Extension Center at Virginia Tech, Hampton, Virginia. Stocking density, tank size, system filtration, and water quality for each system are described in Table 1. Water temperature and dissolved oxygen were measured daily (YSI 550 temperature– oxygen meter; Yellow Springs Instruments, Yellow Springs, Ohio), whereas other water quality conditions (total ammonia nitrogen, nitrite-nitrogen, nitrate-nitrogen, alkalinity, and salinity [Cobia trial only]) were measured weekly for each system (Hach DR 2800 portable spectrophotometer, digital titrator, and reagents; Hach Company, Loveland, Colorado). Water quality conditions were maintained within suitable ranges throughout the trials (Table 1). Practical diets were formulated to meet the known nutritional requirements of hybrid Striped Bass, Rainbow Trout, and Cobia (NRC 2011) and to contain approximately 40:12%, 42:13%, and 45:12% digestible protein : lipid, respectively (Table 2). The diets contained different levels of menhaden fish meal (MFM; Special Select, Omega Protein., Houston, Texas), Asian carp fish meal (CFM; Protein Products, Gainsville, Florida), or a 50:50 blend of these ingredients such that 0% (0 FM), 20% (20 MFM, 20 CFM), 40% (40 MFM, 40 CFM), or 60% (60 MFM, 60 CFM, 60 Blend) of the estimated digestible protein content was derived from a fish meal source. Estimates of digestible protein content were based on apparent digestibility coefficients reported for hybrid Striped Bass and Rainbow Trout (Barrows et al. 2012; Bowzer et al., in press); digestibility coefficients were not available for Cobia; therefore, these feeds were formulated using Rainbow Trout values. Errors were made in the formulation of two diets (10% lipid in 60 MFM diet versus 12% in other diets for Cobia; 45% digestible protein in 60 CFM diet versus 40% in other diets for hybrid Striped Bass). Diets were manufactured and analyzed in triplicate to determine proximate composition (Table 3) using standard methods described in detail by Rombenso et al. (2013). Minor differences resulting from the formulation errors mentioned above and/or inaccuracies in ingredient weighing or mixing were observed; however, these

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TABLE 1. Recirculation system characteristics and water quality observed during feeding trials for hybrid Striped Bass, Rainbow Trout, and Cobia. Water quality values represent least-squares means ± SE.


Parameter Number of tanksa Tank volume (L) Stocking density (fish/tank) Biofiltration Mechanical filtration Aeration Temperature (◦ C) Dissolved oxygen (mg/L) pH Salinity (‰) Alkalinity (mg/L) NO3 −-N (mg/L) NO2 −-N (mg/L) Total ammonia nitrogen (mg/L) a

Hybrid Striped Bass

Rainbow Trout

Cobia

24 150 10 Trickle-down biofilter Bead filter Blower/airstones 23.6 ± 1.1 7.7 ± 0.3 7.7 ± 0.1