Does nutritional history impact on future performance and utilization of plant based diet in common carp?

Abstract

This study investigated the possibility to improve the use of plant based feed in common carp (Cyprinus carpio), via feeding plant based diet from the early life stage. Fry, obtained from larvae produced by common carp broodstock fed with either of two diets viz. fish based diet (F diet) or plant based diet (P diet), were stocked into six earthen ponds in triplicate. Fry obtained from the F- and P- group were also fed with isoproteic (37% crude protein) and isolipidic (6.5% crude lipid) F- and P- diet respectively, for four months to attain juvenile stage. This early feeding period referred as ‘nutritional history F or P', and fish from the respective nutritional histories were denoted as ‘F- or P- fish’. After four months, a crossover experiment was initiated with random distribution of F- and P- fish into twelve cages fixed in the pond. Fish in triplicate cages per treatment group were either fed with their original diets or respective complementary diet for six weeks (C- phase). After six weeks, fish reared with complementary diets were switched to their original diet for another six weeks (O- phase). Growth performance, nutrient utilization, gene expression profile (IGF-1, GH and GHR) and protein metabolism enzyme activity were analysed at the end of both C- and O- phase. During C- phase, higher growth performance and improved nutrient utilization in P- fish and F- fish were recorded when they were fed with their original diet (P/F) compared to the complementary diet (F/P). The decreased growth performance and nutrient utilization of F- fish fed with P diet during the C- phase increased again during the O- phase and resumed to a similar growth performance with F- fish fed with F diet; however P- fish could not resume the same growth performance in the O- phase. Expression patterns of IGF-1 and GHR genes in the liver were concomitant with the growth performance. The present study confirms that nutritional history has a significant impact on nutrient utilization during latter life stages, and nutritional programming at early stage may be the strategy for complete replacement of fish based diet with plant based diet in common carp without compromising the growth performance and nutrient utilization. Conclusively, the findings revealed the profound effect of feeding common carp according to their nutritional history on the later performance of the progeny, as well as effective utilization of the plant based diet.