Judul: Relationship between Starch and Amino Acid Levels of Broiler Diets on Growth Performance and Feed Efficiency
Abstrak: Broiler chicken industry is a very important in Indonesia. Feed efficiency is very necessary to support it. One technique to improve broiler performance is to consider about starch level and the ratio to amino acid in the feed formulation. In addition, protein is composed of amino acids with a certain ratio of the amino acid lysine (ideal protein concept model). Starch is a part of carbohydrate as important energy source for broiler chickens. The amount of starch is still not taken into account in predicting the energy content of a material. Starch provides a more than 50% of energy requirement in broiler feed which based on corn and soybean meal. Starch generally has very high digestibility, but the rate of degradation in the intestine varies (Weurding et al. 2001). Feed with the starch content gradually broken down in the small intestine, will provide continuous glucose into the bloodstream. Glucose in the blood will be responded by the release of insulin which plays an important role in the transport of glucose and protein into muscle during growth (Fox 1996). Continuous availability of glucose to the posterior part of the small intestine, could prevent the use of amino acids as an energy source for the intestinal wall (Weurding et al. 2003). The rate of starch digestibility in the jejunum is faster than the protein (Liu et al. 2013). The existence of the unconformity between the rate of starch digestibility and protein, leading to differences in the growth of chickens given feed wheat and sorghum (Black et al. 2005). The aims of this study was to determine the feeding effect of diets containing different starch and amino acid levels on growth performance and blood parameters. In this study, 240 day old chicks were distributed to 6 treatments using a completely randomized design (CRD) with four replications. Three treatments were fed with high starch (36%) and three others were fed with low starch (32%). Both type of diets were formulated as isocaloric with three levels of total lysine, varying from 1.34%, 1.43%, 1.48% for starter period (0-21 days) and 1.18%, 1.3%, 1.35% for finisher period (21-35 days). Parameters were observed among feed intake, feed conversion, weight gain, blood glucose levels, blood uric acid levels, insulin levels, the absorption of starch in the small intestine and absorption of protein. The result showed that feed containing 36% starch and amino acid based on 1.34% lysine for starter period and 1.18% lysine for finisher period gave the highest weight gain.The feed containing 36% starch and amino acid based on 1.43% lysine for starter period and 1.3% lysine for finisher period gave the best feed conversion. Level of starch and amino acid in the feed affected to the protein absorption, insulin and uric acid level in the blood serum. Ratio starch and amino acid were positively correlated with weight gain (r=0.573, P<0.05) and feed consumption (r=0.550, P<0.01). Starch absorption in the small intestine were positively correlated with weight gain (r=0.461, P<0.05) and negative correlated with feed convertion ratio (r= -0.482, P<0.05). The conclusion of this study was ratio of 36%
Keyword: amino acid, broiler performance, glucose, insulin, starch