Effects of dietary protein levels on the growth performance, digestive capacity and amino acid metabolism of juvenile Jian carp (Cyprinus carpiovar. Jian)

Abstract

This experiment was conducted to evaluate the effects of protein levels on the growth performance, digestive capacity and amino acid metabolism of juvenile Jian carp. Brown fish meal was used as the sole protein source in the present study. Six isoenergetic experimental diets containing 14.4 MJ kg−1 of digestible energy and 220–495 g crude protein kg−1 diets were fed to triplicate groups of 50 fish with a mean initial weight of 16.67 ± 0.01 g for 45 days. Per cent weight gain (PWG) and feed efficiency ratio (FER) improved with an increase in the dietary protein levels up to 330 g kg−1 diet. The condition factor, relative gut length, intestinal folds height, hepatopancreas and intestine protein content improved with an increase in the protein levels up to 330–385 g kg−1 diet. Trypsin, creatinkinase, Na+, K+‐ATPase and alkaline phosphatase activities generally followed the same tendency as that of growth parameters. Amylase and γ‐glutamyl transpeptidase (γ‐GT) activities were negatively correlated with increasing protein levels from 220 to 330 g kg−1 diet, and no differences were found thereafter. Lipase activity was unaffected by protein levels. Lactobacillus amount was increased with protein levels up to 275 g kg−1 diet, while Aeromonas amount followed the opposite pattern. Escherichia coli amount was not influenced by dietary protein levels. Glutamate–oxaloacetate transaminase (GOT) activities in the hepatopancreas and plasma ammonia concentration (PAC) were not influenced by protein levels between 220 and 275 g kg−1 diet, but significantly increased with increasing protein levels from 275 to 440 g kg−1 diet, and remained similar thereafter. Glutamate–pyruvate transaminase (GPT) activities significantly increased with protein levels >275 g kg−1 diet. Based on the broken‐line model, the dietary protein requirement for PWG of Jian carp (16.7–55.0 g) was estimated to be 341 g kg−1 diet with a digestible energy of 14.4 MJ kg−1 diet.

Optimal dietary protein level improved growth, disease resistance, intestinal immune and physical barrier function of young grass carp (Ctenopharyngodon idella)

“…Meanwhile, Kaplan [83] reported that Na þ , K þ -ATPase carries out the uptake of Na þ in most higher eukaryotes. Studies from our laboratory showed that dietary protein supplementation could increase the activity of Na þ , K þ -ATPase in the intestines of Jian carp [84]. Thus, dietary proteins up-regulate claudin 15a (rather than claudin 15b) gene expression, which might be a feedback mechanism for increased Na þ transport capacity in the fish intestine.…”

Optimal Dietary Protein and Lipid Levels for Growth of Juvenile Israeli Carp Cyprinus carpio

“…Jian. (Liu et al, 2009) but is comparable with 40% for fingerling catla Catla catla (Mohanty et al, 1990) and 41.7% for Barbodes altus (Elangovan and Shim, 1997), and lower than 45%-50% for endangered cyprinid Tor putitora (Islam and Tanaka, 2004). Protein requirements among the fish species are complicated by the difference in fish size or age, culture conditions, and nutrient interactions in experimental diets such as protein and non-protein energy levels (NRC, 1993).…”

Supplementation of enzyme-treated soy protein saves dietary protein and promotes digestive and absorptive ability referring to TOR signaling in juvenile fish

“…White fishmeal, soybean meal, cottonseed meal, and rapeseed meal were used as the main protein sources in all the dietary treatments. Diet 1 was formulated to contain protein level of 340.0 g/kg diet, to meet the protein requirement of juvenile Jian carp according to Liu et al (2009). Diet 2 was reduced 2% dietary protein in total by iso-proportionally reducing the amount of four protein materials based on diet 1.…”