Isoleucine requirements of the chicken: The effect of excess leucine and valine on the response to isoleucine

Abstract

1. Three experiments were designed to determine the response of broiler chickens to dietary isoleucine, and to quantify the antagonistic effects of excess leucine and valine on this response. 2. A dilution technique was used to measure the responses in growth rate and food intake to a range of diets differing in their isoleucine concentrations. A summit diet was formulated to contain isoleucine at 1.14 times the requirement and with leucine (1.76 times the requirement) and valine (1.87 times the requirement) at the minimum possible concentrations, given the ingredients available. A dilution mixture, devoid of protein, was formulated to correspond in all respects, other than in amino acid content, to the summit diet. These two basal diets were blended in different proportions to give a range of diets of decreasing isoleucine and protein content. 3. In experiment 1 the response was measured to isoleucine with leucine and valine remaining in the same proportion to isoleucine throughout the range of diets fed. In experiments 2 and 3, however, L-leucine and L-valine were added to the diets either singly or in combination to give 6 isoleucine concentrations and 3 ratios of each of leucine and valine to isoleucine. 4. Weight gain decreased as the isoleucine content of the diet was reduced, whereas food intake of broilers fed on the marginally deficient diets increased to a maximum and then decreased. FCE decreased curvilinearly as the isoleucine concentration in the food decreased, reflecting a concomitant change in the fat content of the broilers. 5. It is possible that the amount of dietary isoleucine assumed to be available to the broilers in these experiments was overestimated by hydrolysing the food samples for 72 h, and the doubt thus created makes an estimate of the efficiency of retention of isoleucine suspect. 6. Excess valine had no effect on the response to isoleucine, whereas an increase in the leucine to isoleucine ratio depressed food intake and hence weight gain, but only at the lowest concentrations of isoleucine. 7. If the food content of isoleucine is sufficient to meet the requirements of the broiler, relatively large excesses of leucine, of valine, or of both will not depress growth.

Growth, Digestive Tract and Muscle Weights in Slow-Growing Broiler is not Affected by a Blend of Branched-Chain Amino Acids Injected into Different Sites of Egg

“…Indeed, Burnham et al (1992) reported that in case of diet isoleucine content is below the needs of poultry, the high levels of leucine and valine adversely affect the weight gain. Relatively large excesses of leucine and of valine, or of both do not depress growth, because if the dietary content of isoleucine is sufficient to meet the requirements of the broiler (Burnham et al, 1992;Ospina-Rojas et al, 2014). These suggestions indicate that each of amino acid in our BCAA blend was not below the needs of embryo or not excess any one of these amino acids.…”

“…Therefore, our results indicate that the nutrient contents of eggs used in the present trial was in ideal levels, which could not affect the hatchability, chick quality and the degree of growth promotion. It is known that well-nourished, healthy chicks do not respond to in ovo supplements (Schulte-Drüggelte, 2015) and the degree of limiting protein synthesis of these amino acids depend on the ratios and antagonistic relationship between each of these amino acids Burnham et al, 1992) and the protein content and quality of poultry diets (Corzo et al, 2009(Corzo et al, , 2010Ospina-Rojas et al, 2014). Indeed, Burnham et al (1992) reported that in case of diet isoleucine content is below the needs of poultry, the high levels of leucine and valine adversely affect the weight gain.…”

“…It is known that well-nourished, healthy chicks do not respond to in ovo supplements (Schulte-Drüggelte, 2015) and the degree of limiting protein synthesis of these amino acids depend on the ratios and antagonistic relationship between each of these amino acids Burnham et al, 1992) and the protein content and quality of poultry diets (Corzo et al, 2009(Corzo et al, , 2010Ospina-Rojas et al, 2014). Indeed, Burnham et al (1992) reported that in case of diet isoleucine content is below the needs of poultry, the high levels of leucine and valine adversely affect the weight gain. Relatively large excesses of leucine and of valine, or of both do not depress growth, because if the dietary content of isoleucine is sufficient to meet the requirements of the broiler (Burnham et al, 1992;Ospina-Rojas et al, 2014).…”

Bootstrapped neural network models for analyzing the responses of broiler chicks to dietary protein and branched chain amino acids

“…To address the objectives of this study, 270 lines of broiler chick dose responses (ADG and FE) to protein and BCAA were extracted from the literature, comprising experiments conducted during 1990Á2013 Thomas 1990, 1992;Barbour and Latshaw 1992;Burnham et al 1992;Waldroup et al 2002;Farran et al 2003;Yamazaki et al 2006;Tavernari et al 2013). The dietary levels of protein, isoleucine, leucine, and valine (g kg (1 of diet) were considered as input variables, while ADG and FE were the variables of interest for model output.…”

The response of weaned piglets to dietary valine and leucine

“…A probable reason for this is that at the highest protein level the ratio of energy : protein was below the threshold of 73 MJ ME/kg digestible CP required to ensure maximal efficiency of utilisation of the protein Emmans, 1992a and1992b). When feed Val content dropped below 8.3 g/kg, the resultant sharp decrease in feed intake can be ascribed to the combined effect of an imbalance between that nutrient and energy and a reduced growth rate (Burnham et al, 1992). Higher energy levels should be used in the future when such high dietary protein levels are used in the summit feeds.…”