Annual Research & Review in Biology 4(6): 985-997, 2014
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Variation in the Biochemical Constituents during Different Moulting Stages in Green Tiger Shrimp, Peneaus semisulcatus Bilal Ahmad Paray1, A. Jawahar Ali1*, Mehrajuddin War1 and M. S. Arun Kumar1 1
PG and Research Department of Zoology, The New College (Autonomous), Chennai – 600 014, India. Authors’ contributions
This work was carried out in collaboration between all authors. Authors BAP and AJA and MW designed the study, performed the statistical analysis, wrote the protocol, and wrote the first draft of the manuscript. Author MSAK managed the analyses of the study and the literature searches. All authors read and approved the final manuscript.
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Original Research Article
Received 3 July 2013 th Accepted 26 November 2013 th Published 14 December 2013
ABSTRACT A hallmark of crustacean physiology is the periodic shedding of their old exoskeleton achieved by moulting as an external manifestation of a discontinuous growth process. Crustacean metabolism, reproduction and behavior are all affected by the periodic shedding of the exoskeleton and the characteristics of moulting cycles. There are major gaps in our understanding of moulting patterns of commercially raised shrimp; hence, further investigations on the duration of each moult stage, in-moult cycle and the relationship between biochemical constituents and moult cycling are essentially needed. The present research work was aimed at describing characteristic features and biochemical changes that occur at various stages (A-D) during moulting cycle of the Indian green tiger shrimp Penaeus semisulcatus. Experimental animals (wet weight, 20 ± 2 g) were reared individually in aerated plastic aquaria under normal laboratory conditions (12L: 12D; 28.2ºC) and 50% of the water was replaced daily for one month. Animals were provided twice daily with commercial Magnum Scampi feed ad libitum and were observed regularly for moulting by setal development and biochemical analysis in conjunction with established parameters for morphological changes during the moulting cycle. Results ____________________________________________________________________________________________ *Corresponding author: Email:
[email protected];
Annual Research &Review in Biology, 4(6): 985-997, 2014
showed that muscle protein content peaked during the post-moult stage A (51.23 2.51 mg/g) and gradually declined through the inter-moult and pre-moult stages. Similarly in the hepatopancreas, distinct increase in the total protein content was observed during the post-moult stage B (15.78 0.26 mg/g) and a steady decline was noticed thereafter (p < 0.05). Significantly higher levels of total sugars from muscle tissues were observed in late post-moult stage B (51.23 2.65 mg/g) and minimum level of total sugars were observed in late pre-moult stage D2-3 both in muscle tissue (28.43 2.98 mg/g) and in hepatopancreas (18.79 1.62 mg/g). A sharp fall in lipid content of muscle tissues was observed in inter-moult stage C (19.54 1.45 mg/g) and a corresponding decline (48.21 3.25 mg/g) was observed in the hepatopancreas. The present study documents and further expands our understanding of the physiological and biochemical changes occurring in P. semisulcatusduring four different moulting stages and will provide useful criteria for identifying different stages in the life cycle of this commercially farmed shrimp. Keywords: P. Semisulcatus; moulting; biochemical changes; physiology.
1. INTRODUCTION One of the important aspects of crustacean physiology is the periodic shedding of old exoskeleton which is accomplished by moulting, an external manifestation of discontinuous growth process. The actual preparation for the subsequent moult, however, consists of numerous biochemical, physiological and morphological changes that temporally occupy much of the proceeding moult cycle [1]. The classical work of [1] made it possible to recognize three major moult stages such as inter-moult, pre-moult, and post-moult, which are further subdivided into several sub stages. The inter-moult is the interval between two successive moults, whereas the pre-moult and post-moult represent the preparatory as well as post-ecdysial stages, respectively. The schedule of moult staging on the basis of setal development has been described in many Penaeid species [2,3,4,5,6,7]. Preliminary studies on the moult staging of Penaeus indicus were carried out by [8,9,10] and for tiger shrimp Penaeus monodon by [11]. In this study, Indian green tiger shrimp Penaeus semisulcatus has been selected because of its growing importance for shrimp farming in the Indian sub-continent where its farming has been standardized. However, there is a great need to fill gaps in our knowledge on moulting patterns of this commercially important shrimp. The current basic problems of importance that need further investigation, include the duration of each moult stage within the moult cycle and the relationship between biochemical constituents and moult cycle. Metabolism, reproduction and behavior are affected both directly and indirectly by the periodic shedding of the exoskeleton [12]. The present study was restricted to study some characteristic features and biochemical changes in macromolecular components such as total proteins, total sugars and total lipids during various stages of moult cycle in the marine green tiger shrimp, P. semisulcatus.
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Annual Research &Review in Biology, 4(6): 985-997, 2014
2. MATERIALS AND METHODS 2.1 Collection of Shrimps Adult fresh live shrimps, P. semisulcatus, were obtained from fishermen at fish landing center in Kasimedu, Chennai and stocked in large rectangular cement aquaria (90 × 60 × 60 cm; 175 L capacity) with adequate aeration. Experimental animals (wet weight, 20 ± 2 g) were reared individually in aerated plastic aquaria (16 L capacity) under normal laboratory conditions (12L: 12D; 28.2ºC) and 50% the water was exchanged every day for a month. Animals were fed, ad libitum, commercially available feed (Magnum Scampi feed; 31% crude protein, 4% crude fat, 7% crude fiber and 11% moisture) twice a day (08.00 h and 18.00 h) and were observed regularly for moulting.
2.2 Analysis of Moult Stages Setal development of P. semisulcatus was observed at the posterior median part of the pleopods and uropods. Moult stages were determined based on morphological changes of the seta as described by [1] using light microscope (Labex, India). The pleopods and uropods were removed, mounted on a microscope slide in filtered sea water and stages of moulting were recorded with CCD micro-imaging systems (CCD_MODULE_BME_C_721, Korea).
2.3 Estimation of Total Protein, Sugars and Lipids Total protein and sugars of muscle and hepatopancreas were quantified following the method of [13] and [14] respectively. Total lipid was quantified according to [15] and extraction of lipids from the samples was done as described by [16].
2.4 Statistical Analysis Data obtained from biochemical analysis with reference to proteins, sugars and lipids at various stages of moulting were subjected to analysis of variance (ANOVA) and difference between different stages of moulting were determined by Duncun’s test. Data are presented as mean ± SD. The values of P
