DIETARY INFLUENCES ON PRODUCT QUALITY IN AFRICAN CATFISH (CLARIAS-GARIEPINUS)

In this trial a full-sib family of Clarias gariepinus was raised under standard conditions in a warmwater recirculation system. The fish wer e divided into two experimental groups of 1200 individuals each and we re raised in separate tanks. The groups were fed two experimental diet s differing in crude protein (group I 40% and group II 52% DM) and cru de fat (group I 8% and group II 13% DM). Gross energy was 21.3 and 22. 1 MJ/kg. Slaughtering of 100 fish per group (50 males, 50 females) too k place after two experimental periods. Besides the significant effect of the diets on body weight and size, a higher degree of corpulence w as observed in group II. Tissue and organ percentages were not influen ced, except a higher intestinal fat deposition in intensively fed fish . This group also showed a higher carcass weight. More expressed diffe rences between both feeding alternatives were observed in physical and chemical flesh quality criteria. In group I texture of flesh was firm and water-binding-capacity was significantly increased in group II. T he appearance of the filer was affected by the diet. Intensively fed c atfish showed a tendency to a lighter and more yellowish colour. The c hemical composition of the flesh indicated a significant increase of d ry matter caused by higher protein and fat contents in this group. A s trong influence of sex and fattening age on inner and outer product qu ality was evident. High fat and protein content of the diet has a cert ain influence on product quality in African catfish. It can be conclud ed that there is a clear effect of diet on quantitative criteria with a tendency to higher slaughtering yields in intensively fed catfish.