Dietary leucine requirement of fingerling Indian major carp, Labeo rohita (Hamilton)

Abstract

An 8-week feeding experiment was conducted to evaluate the dietary leucine requirement of ¢ngerling Indian major carp, Labeo rohita (3.50 AE 0.04 cm; 0.40 AE 0.02 g) using amino acid test diets (40% crude protein; 17.90 kJ g À1 gross energy) containing casein and gelatin as intact protein sources and L-crystalline amino acids. Growth performance and biochemical parameters were assessed by feeding six amino acid test diets supplemented with graded concentrations of leucine (0.75, 1.0, 1.25, 1.50, 1.75 and 2.0 g per 100 g) to triplicate groups of ¢ngerlings to apparent satiation divided over two feedings at 07:00 and 17:30 hours. Performance of the ¢sh was evaluated on the basis of live weight gain, feed conversion ratio (FCR), protein e⁄ciency ratio (PER) and body protein deposition (BPD) data. Maximum live weight gain (315%), best FCR (1.35), highest PER (1.86) and BPD (33.9) were recorded at 1.50 g per 100 g dietary leucine. Statistical analysis of live weight gain, FCR, PER and BPD data re£ected signi¢cant di¡erences (Po0.05) among treatments. Live weight gain, FCR, PER and BPD data were also analysed using second-degree polynomial regression analysis to obtain more accurate leucine requirement estimate which was found to be at 1.57, 1.55, 1.52 and 1.50 g per 100 g of dry diet, corresponding to 3.92, 3.87, 3.80 and 3.75 g per 100 g of dietary protein respectively. Based on the quadratic regression analysis of the live weight gain, FCR, PER and BPD data, the optimum requirement of ¢ngerling L. rohita for leucine is estimated to be in the range of 1.50^1.57 g per 100 g of the dry diet, corresponding to 3.75^3.92 g per 100 g of dietary protein.

Dietary leucine requirement for juvenile large yellow croaker Pseudosciaena crocea (Richardson, 1846)

“…The result is close to that of 6.98% of dietary protein for bluntnose black bream (Megalobrama amblycephala) (Li, 1996), but higher than those reported for many other fish, e.g. 3.75%−3.92% of dietary protein for Indian major carp (Hamilton) (Abidi and Khan, 2007), 5.2% of dietary protein for Atlantic salmon (Salmon salar L.) (Rollin, 1999), 3.7% of dietary protein for catla (Catla cacia) (Ravi and Devaraj, 1991), 3.5% of dietary protein for channal catfish (Ictalurus punctatus) (Wilson et al, 1980), 3.9% of dietary protein for chinook salmon (Oncorhynchus keta) (Chance et al, 1964) and 4.3% of dietary protein for both European seabass (Morone labrax) (Kaushik, 1998) and white sturgeon (Acipenser transmontanus) (Ng and Hung, 1995).…”

“…Although leucine is considered to be essential for normal growth and reproductive potential of fish, imbalance of dietary leucine could lead to a reduction in growth rate (Abidi and Khan, 2007). In the present study, higher amount of leucine was found to depress the growth of large yellow croaker.…”

“…In the present study, higher amount of leucine was found to depress the growth of large yellow croaker. This is probably due to the fact that excessive leucine leads to accumulation and oxidation to ketones and other toxic metabolites adversely affecting fish growth (Abidi and Khan, 2007). It is also possible that antagonism among amino acids inhibits the growth.…”

Differential growth performance, intestinal antioxidant status and relative expression of Nrf2 and its target genes in young grass carp (Ctenopharyngodon idella) fed with graded levels of leucine

“…These negative effects of leucine at high level may be related to accumulation of leucine itself or its metabolites. Abidi and Khan (2007) indicated that excessive leucine leads to the high oxidation to ketones and accumulation of other toxic metabolite. In cerebral cortex of rats, the accumulation of leucine and its metabolite inhibited activities of antioxidant enzymes CAT and GPx, thus leading to oxidative damage (Bridi et al, 2005).…”

Dietary leucine improves flesh quality and alters mRNA expressions of Nrf2-mediated antioxidant enzymes in the muscle of grass carp ( Ctenopharyngodon idella )

“…The dietary protein level was fixed at 300 g kg − 1 , reported optimum for the growth of grass carp (Khan et al, 2004). The mixture of crystalline amino acids without leucine was prepared according to the method described by Abidi and Khan (2007). Our previous study observed that the optimal leucine requirement for growth is 13.0 g kg −1 diet (Deng et al, 2014).…”