Utilization of torula yeast (Candida utilis) as a protein source in diets for tilapia (Oreochromis mossambicus Peters) fry

M.A. Olvera-Novoa, C.A. Martinez-Palacios, L. Olivera-Castillo-2002

Aquaculture Nutrition, 8(4): 257-265

Abstract:

A 63-day feeding trial was conducted under laboratory conditions to evaluate the effects of substituting animal protein with a mixture of plant feedstuffs including 25, 30, 35, 40 and 45% of the protein with torula yeast (Candida utilis), 20% with soybean meal and 15% with Alfalfa Leaf Protein Concentrate (ALC), in diets for tilapia (Oreochromis mossambicus Peters) fry. Feeding efficiency was compared against a diet with fish meal as the sole protein source. Diet nutritional quality was very similar independent of composition, with no differences in growth parameters, but fish fed with 30% yeast diet showed the best growth performance. Diet composition did not affect feed or protein utilization, with the best feed conversion ratio, protein efficiency ratio and apparent nitrogen utilization in the 25% yeast diet. Protein digestibility was above 80% for all diets, and no differences in carcass composition were observed. The best incidence cost was obtained with 25% yeast and the highest profit index with 30% yeast, but no statistical differences were observed with the other treatments. The results suggest that it is possible to replace up to 65% of animal protein with a mixture of plant proteins, including 30% from torula yeast, in tilapia fry diets without adverse effects on fish performance and culture profit.

(Centro de Investigación y de Estudios Avanzados del IPN, Unidad Mérida (CINVESTAV), Mérida, Yucatán, México)

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