An analysis of the effect of diet and genotype on protein and energy utilization by the black tiger shrimp,Penaeus monodon- why do genetically selected shrimp grow faster?

Abstract

Selected (G8) and wild-type (W) genotypes of black tiger shrimp (Penaeus monodon) juveniles (initial weight G8 = 9.14 ± 0.36 g per animal and W = 8.44 ± 0.10 g per animal) were fed either of two diet types in a clear-water tank trial to examine the effects of diet type and genetics on growth and feed utilization parameters. Animals were fed twice daily at one of the five ration levels from starvation to apparent satiety. All uneaten feed was accounted for and moults removed. Starved animals were measured after 3 weeks; those fed were measured at both three and 6 weeks. Diet type varied by protein content, raw material choice and the presence [high-specification diet (HSD)] or absence [low-specification diet (LSD)] of bioactive substances. At the end of the study, faecal samples were also collected to determine the digestible protein and energy content of each diet by each genotype. Whole animal protein and energy content were also assessed from samples from the initial populations and those from each tank. Growth after 6 weeks of those animals fed to satiety showed that the G8 animals fed the HSD diet had grown at a rate of 2.56 g week À1 , significantly faster than any other treatment. Those G8 animals fed the LSD diet (1.81 g week À1 ) had grown significantly faster than the W animals fed the HSD diet (1.25 g week À1 ), while those W animals fed the LSD diet (0.61 g week À1 ) grew the slowest. Using the data from the varying ration levels, we were able to define that the growth gains of the G8 animals were achieved not only by a greater appetite, but also through lower maintenance energy costs (29 versus 57 kJ kg À0.8 day À1 ) and a more efficient energy conversion (19.5% versus 11.6% when fed the HSD diet). Use of a low-specification diet with the G8 and W shrimps limited their growth and impaired their potential as demonstrated by a curvilinear response of growth to intake. By comparison, those shrimp fed the HSD diet had a relatively linear growth response to intake.

Aquaculture: a rapidly growing and significant source of sustainable food? Status, transitions and potential

“…Potentially, their role in adding value to wastes through production of a quality feed ingredient can be achieved with minimal competition for resources. Similarly, the use of waste or low-value feedstocks for microbial and fungal protein has resulted in mature technologies and products, some of which already have full regulatory approval for use in livestock feeds (71) or are already in the marketplace supporting the move of shrimps away from reliance on marine ingredients (72) . The higher relative interest in these products by the aquatic rather than the terrestrial sector reflects the former's continued dependence on high trophic species for marine ingredients.…”

Improving the Reproductive Performance of Domesticated Giant Tiger Shrimp, Penaeus monodon

“…The present study suggests that, in addition to promoting growth in juvenile shrimp , Glencross et al, 2013, the inclusion of dried MB within pelleted diets may enhance reproductive performance in domesticated P. monodon broodstock.…”

“…The growth promoting effects of microbial biomass on shrimp have been reported in a number of studies (Burford et al, 2004, Kuhn et al, 2008, Kuhn et al, 2009. Nutritional studies have demonstrated that the growth enhancing effects are critically dependent on meeting the overall nutritional demands of shrimp (Glencross et al, 2013.…”

“…Targeted traits include increased growth (Glencross et al, 2013), harvest yields ) and viral tolerance , Sellars et al, 2015a. Given the prevalence of growth selection in P. monodon hatcheries, Macbeth et al (2007) calculated the degree of genetic correlation between growth and nauplii production.…”

“…These include superior growth and feed utilization (Glencross et al, 2013, increased harvest yields (Preston et al, 2009) and increased viral tolerance (Sellars et al, 2015a). Despite these improvements, the reproductive performance of domesticated broodstock remains inferior when compared with wild-caught broodstock , Peixoto et al, 2005, Coman et al, 2006.…”