Effect of Arginine Supplementation on the Growth, Blood Biochemical Parameters and Intestinal Histology in Asian Red-tailed Catfish (Hemibagrus wyckioides) Fed with Diets of Plant Protein Replaced Fish Meal

Purprose We investigated the impact of replacing fish meal with plant-based protein on the growth and physiology in Hemibagrus wyckioides, and the rescuing effect of Arg on them.

MethodA total of 375 healthy juvenile H. wyckioides (initial weight 6.40 g±0.06 g) were randomized to five equal groups with 3 replicates, which were fed five diets containing whole fish meal (FM group), replacing 25% fish meal (25% I group), replacing 25% fish meal + 1.5% Arg (25% II group), replacing 50% fish meal (50% I group), replacing 50% fish meal + 1.5% Arg (50% II group), respectively. The growth performance of each group was measured during the 8 weeks feeding trial. After the rearing test, the blood biochemical index and intestinal tissue structure of experimental fish in each treatment group were measured using Kit (Nanjing jiancheng) and paraffin section method, respectively.

ResultAmong the five diet groups, the specific growth rate (SGR) and crude protein content of H. wyckioides in 50% I group were lowest, significantly lower than FM group (P<0.05). While, the feed conversion ratio (FCR) in 50% I group was highest, significantly higher than FM group (P<0.05). Meanwhile, the blood urea nitrogen (UN) of H. wyckioides in 25% I and 50% I groups were higher than FM group (P<0.05). Those result suggested that the growth performance and body protein deposition of H. wyckioides was decreased and the level of blood urea nitrogen was increased with increasing replacement ratio. After the Arg-mediated, the growth and biochemical indicators of H. wyckioides in 50% II group showed no significant difference with those in FM group (P>0.05). Intestinal morphology analysis indicated that the midgut villus height of H. wyckioides in 25% I, 50% I and 50% II groups were significantly lower than FM group, respectively (P<0.05). The midgut villus width of H. wyckioides in 50% I group was significantly lower than 25% I, 25% II and FM groups (P<0.05). A higher number of goblet cells in 50% I and 50% II groups were observed among the five groups (P<0.05). The integrity and health of the midgut of H. wyckioides in five experimental groups were evaluated as follows: FM≥25% II≥25% I > 50% II > 50% I.

ConclusionIt has a negative effect on growth, physiological and biochemical and intestinal health of H. wyckioides, when plant protein replaces more than 50% of fish meal. The optimal substitution quantity of replacing fish meal with plant-based protein is 25%~50%. Addition of 1.5% Arg can alleviate the inhibition of plant proteins on growth and help to repair intestinal health.