Amino Acid Limitations of Yeast Single-Cell Protein for Growing Chickens

Abstract

Four experiments were conducted to determine the amino acid limitations of yeast single-cell protein (YSCP) when fed as the only source of protein in semipurified diets for broiler chicks. The results of two experiments showed that methionine and arginine were the first and second most limiting amino acids, respectively, in YSCP for chick growth and feed efficiency. On a calculated basis, YSCP seemed to be deficient in leucine, but leucine supplementation of YSCP diets did not improve chick performance. Weight gain and feed efficiency of chicks fed YSCP diets supplemented with amino acids were inferior to those of chicks fed diets in which soy protein was used. When feed intake was equalized by pair-feeding the soy protein diet with the amino acid supplemented-YSCP diet, chick performance was similar irrespective of protein source. Also, the use of a granular form of YSCP in diets improved chick performance as compared with the use of YSCP in powder form. Data obtained from this research show that methionine and arginine are the most limiting amino acids in the YSCP tested. Also, these data suggest that, when the palatability factor associated with YSCP is alleviated and proper amino acid supplementation is used, YSCP can be fed successfully as the sole source of protein in semipurified diets for chicks. (

Types, properties and processing of bio-based animal feed

“…Yeast has been considered as a protein source in animal feed for many years. It has been fed successfully to chicks at up to 10% total dietary inclusion (Yalcin et al ., 1993 ;Onol and Yalcin, 1995 ), but higher levels have depressed performance, due to defi ciencies in some amino acids (Klose and Fevold, 1945 ;Caballero-Cordoba and Sgarbieri, 2000 ) and issues with palatability and texture (Sell et al ., 1981 ;Daghir and Sell, 1982 ;Succi et al ., 1980 ). In fi sh, yeast has been used to replace 50% fi shmeal, with no signifi cant differences in growth and improved protein conversion (Oliva-Teles and Goncalves, 2001 ).…”

Uso de levedura seca (>i<Saccharomyces cerevisiae>/i<) de destilarias de álcool de cana-de-açúcar em rações isocalóricas para suínos em crescimento e acabamento

“…Quando utilizada em alto nível, a levedg ra tornou a dieta muito pulverulenta e desenvolveu uma con sistência viscosa na boca de animais (TEGBE e ZIMMERMAN, 1977 e VALDIVIE e ELIAS, 197 8bl . Este problema pode ser sanado atr� vês da peletização da raçao, o que melhorou o valor nutritivo da levedura(YALDIVIE e ELIAS, 1978be DAGHIR e SELL, 1982.Outra qualidade das leveduras secas e sua boa conservaçao, quando embaladas adequadamente(DESMONTS, 1968). Em exame microbiológico foi verificada a presença apenas de Baeillu� Jubtili� em levedura, o que já era esperado devido a sua normal presença no meio ambiente(MOURA, 197 8) .…”