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1、Effect of dietary protein level on growth and energy utilization by Litopenaeus stylirostris under laboratory conditionsF. Gauquelin a, G. Cuzon a, G. Gaxiola b, C. Rosas b, L. Arena b,D.P Bureau c, J.C. Cochard aa Ifremer/COP, BP 7004 Taravao, Tahiti, French Polynesiab UNAM Unidad Multidisciplinara
2、 de Docencia e Investigacin, Facultad de Ciencias, Sisal, Yucatn Lab Ecophysiologia, Sisal, Yucatan, Mexicoc Fish Nutrition Research Lab, University of Guelph, Ontario, Canada N1G 2W1Received 21 November 2005; received in revised form 24 April 2006; accepted 15 May 2006AbstractA study was conducted
3、using a bioenergetics approach to generate information on energy requirement and feed utilization of Litopenaeus stylirostris. Animals (initial mean weight 211 g were fed ad libitum six experimental diets, ranging from 25 to 58% crude protein (CP), for 50 days.Weight gain increased from 21 to 30 g w
4、ith increasing dietary protein level. Survival rates averaged 80%. Basal metabolism (HeE) and heat increment of feeding (HiE) were monitored using respirometry. HeE was on average 1 kJ shrimp1 day1 or 47 kJ kg live weight1 day (22 kJ/kg0.8. d1), slightly more than what is observed in fish. HiE avera
5、ged 0.2 kJ/shrimp1 day1 or 10 kJ kg live weight1 day1 (4 kJ/kg0.8 d1). It represented 31% and 12% digestible energy intake (DEI) for shrimp fed on 58% CP and 25% CP diet respectively. Non-fecal (UE+ZE) energy calculated on the basis of N-ammonia excretion averaged 0.2 g N-ammonia/g dry wt./ mn or 25
6、 J live shrimp1 day1 in fasting stage and increased to 40 J in post-prandial stage. Ammonia production increased with increasing dietary crude protein (CP). The O:N ratio indicated that protein was increasingly used as an energy substrate as CP increased. The information was used to construct an ene
7、rgy budget for shrimp fed a protypical 40% CP diet. Gross energy intake (IE) was estimated at 6.5 kJ live shrimp1 day1; digestible energy intake (DEI) at 5, urinary and branchial excretion (UE+ZE) at 1.2, total heat production (HE) at 3.2; recovered energy (RE) at 0.6 (or 11%DEI). L. stylirostris ad
8、ults issued from domesticated strain appeared to be more efficiently utilizing (i.e. converting into carcass energy) protein than carbohydrates. This preliminary energy budget can be used to construct theoretical feed requirement and waste outputs model for L. stylirostris. 2007 Published by Elsevie
9、r B.V.Keywords: L. stylirostris; Dietary protein; Growth; Excretion; Respiration1. IntroductionThe blue shrimp Litopenaeus stylirostris was domesticated in Tahiti over the past 25 years and led to identify a specific pathogen resistant strain (SPR40). This species is currently farmed in semi-intensi
10、ve conditions in New Caledonia. However, a gradual increase of mortality has been noticed since 1993 (Mermoud et al., 1998). High mortality rates appear to be related to a progressive degradation of the pond ecosystem and water quality problems. This degradation is likely partly due to management, o
11、verfeeding, and/or variation in feed quality. Incomplete removal of mud and/or insufficient pond drying time between production cycles can affect water quality and productivity. However, poor feeding management (excessive feeding) and/or poor utilization of feed by the animal themselves (Burford and
12、 Williams,2001) remain a major concern.There is consequently a need to improve our knowledge on feed utilization by L. stylirostris. Bioenergetics approaches have been effectively used to predict growth,feed requirement and utilization, and waste outputs of different fish species (Cho and Kaushik, 1
13、990; Cho, 1991;Cho and Bureau, 1998; Elliot and Hurley, 1999; Kaushik,1998; Lupatsch et al., 1998; Cui and Xie, 1999; Bureauet al., 2002; Zhou et al., 2005). In contrast, for crustacean species, notably penaeid shrimp information is limited (Bureau et al., 2000). Data from crustaceans are difficult
14、to interpret due to wide differences in species, development stages, feed composition, feeding rate and estimation of feed consumption then nutrient intake. And because of a lack of data on L. stylirostris some estimates on main parameters collected on different species were necessary to review brie
15、fly in order to set a same order of magnitude for each parameters contributing to the energy budget. Sick and Andrew (1972) estimatedHP (HE,HeE+HiE) feeding Macrobrachiumlarvae (7mgav. wt.) tobe on average0.2 Jmg1 live weight day1. Similar data were reported and presented for post-larvae of the same
16、 species, since Stephenson and Knight (1980) observed that Macrobrachium post-larvae respired 0.24 J mg1 live weight day1.These values appeared to be high in comparison with estimated HE of lobster post-larvae (stages IV and V) at about 0.06 J post-larvae1 day1 (Capuzzo and Lancaster,1979). ButMarsh et al. (2001) measured 3 J larvae1 day1 from zoea to megalope (2 wk) stages of Hemigrapsus crassipes. Similarly, F. brasiliensis larvae respired 3 J larvae1 day1 (Gaxio
