Hydrolyzed Feather Meal in Diet of Yellow Catfish (Pelteobagrus Fulvidraco): Effects on Growth Performance, Flesh Quality, Skin Color and Intestinal Flora

Abstract

An eight-week feeding experiment was conducted to evaluate the effects of replacing fish meal with hydrolyzed feather meal (HFM) on the growth, flesh quality, skin color and intestinal flora of yellow catfish (Tachysurus fulvidraco). Five isonitrogen (44% crude protein) and isolipidic (8.5% crude lipid) diets were formulated with 0% (FM, control), 2.05% (HFM2), 4.10% (HFM4), 6.15% (HFM6) and 8.20% (HFM8) HFM inclusion to replace 0%, 8.33%, 16.67%, 25% and 33.33% of fish meal in the control diet, respectively. The results revealed that the growth performance was gradually depressed (P < 0.05) with the increasing replacement levels. Based on the results of weight gain rate and specific growth rate, the maximal replacement levels of fishmeal with HFM for yellow catfish should be 16.67%. The activities of intestinal trypsin, lipase, amylase and Na+-K+-ATPase as well as villus height, villus height/crypt depth, muscular thickness were significantly elevated (P < 0.05) in HFM inclusion groups. Fish meal replacement with HFM remarkably reduced serum immune indicators acid phosphatase, immunoglobulin M, complement 3 and complement 4 levels (P < 0.05) and significantly increased serum aspartate aminotransferase, total triglycerides and cholesterol levels (P < 0.05), indicating the impaired serum immune system and liver dysfunction. The content of collagen, flavor amino acids glutamic acid, glycine and alanine as well as muscle hardness were distinctly boosted (P < 0.05), demonstrated an elevated flesh texture led by dietary HFM inclusion. The abnormal skin coloration induced by pigmentary disorders was observed in high HFM inclusion groups. The fish meal replacement with HFM re-shaped intestinal flora.

Keywords: Tachysurus fulvidraco, hydrolyzed feather meal, growth, flesh quality, intestinal flora