ARS | Publication request: EFFECT OF DIETARY LYSINE AND GENETICS ON INDICES OF ENERGY AND PROTEIN METABOLISM IN RAINBOW TROUT

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: November 15, 2007
Publication Date: April 8, 2008
Citation: Cleveland, B.M., Blemings, K.P., Silverstein, J., Pomeroy, S., Barrows, F. 2008. Effect of dietary lysine and genetics on indices of energy and protein metabolism in rainbow trout. Meeting Abstract. 22:869.9.

Technical Abstract: Since feed cost represents about 70% of production cost, inexpensive protein alternatives are desirable replacements for fish meal. One drawback to the replacement of fish meal with soybean meal is that the latter protein source is first limiting in lysine. To investigate if different genetic lines of fish would respond differently to a lysine-deficient (LD) diet, five families with high feed efficiency and 5 with low feed efficiency were studied. These 10 families were fed a LD, soybean meal containing, diet. The highest and lowest feed efficiency families also received a lysine-adequate (LA) diet as a positive control. For each diet x family treatment combination, 5 replicates were used. Feed efficiency and thermal growth coefficient were greater (P<0.05) while hepatic somatic index (HSI) and ammonia excretion were lower (P<0.05) for fish fed the LA diet. There was a family effect on feed efficiency (P<0.0001) and thermal growth coefficient (P<0.0001), but not ammonia excretion, HSI, or indices of lysine catabolism. A single family had a numerically more favorable feed efficiency and thermal growth coefficient, when fed the LD diet, indicating that it may possess an enhanced genetic potential for performance when consuming lysine-deficient, soybean meal containing diets.