Increased Breast Meat Yield Research Articles

Replacement value of betaine for DL-methionine in male broiler chicks

The effect of DL-methionine and betaine supplementation on growth performance of 2,400 male broilers in the age period of 1 to 38 d, and on carcass composition of a subsample of 384 birds was examined. Three dose levels of DL-methionine (0, 0.05, and 0.10%) and two doses of betaine (0 and 0.04%) were supplemented in different combinations to methioninedeficient diets. Two types of diets were fed as starters and growers: either corn-soybean diets or practical diets typical for the Dutch broiler industry. All diets were fortified with 220 ppm choline in order to avoid a deficiency in methyl groups. Increasing DL-methionine supplementation significantly improved daily weight gain and feed conversion efficiency. Supplemental betaine did not affect bird growth. Betaine slightly improved feed conversion in diets without supplemental DL-methionine, but did not affect this parameter in diets with added DL-methionine. Breast meat yield was significantly increased by about 1.5 percentage points by the addition of 0.05% DL-methionine, whereas 0.04% betaine only tended to increase breast meat yield in the range of 0.3 to 0.6 percentage points. The type of diet did not have any effect on the responses obtained. In summary, there was no evidence for betaine to spare DL-methionine as an essential amino acid supplement in broiler diets.

The effect of altering the dietary arginine to lysine ratio on the breast meat yield of broiler chickens at moderate and high temperatures

In 4 experiments broilers were housed at moderate or high temperatures and fed diets containing arginine : lysine (arg : lys) ratios ranging from 1·01 to 1·45 from 3 weeks of age until reaching a processing weight of 2·2 kg. The effects of temperature and arg : lys ratio on breast meat yield were determined. In the first 3 experiments, increasing the arg : lys ratio increased breast meat yield at moderate temperatures and reduced breast meat yield at high temperatures. Hypothesised response curves are presented to explain the different responses in breast meat yield to arg : lys ratio at moderate and high temperatures. Expt 4 was designed to test the validity of the hypothesised response curves. The pattern of the responses obtained from this experiment supports the hypothesis.

Effects of Dietary Protein Under High Ambient Temperature on Body Weight, Breast Meat Yield, and Abdominal Fat Deposition of Broiler Stocks Differing in Growth Rate and Fatness

The effect of dietary protein on growth, feed intake and efficiency, abdominal fat deposition, and breast meat yield was investigated in broiler males from a commercial stock (WI) and from experimental stocks selected for low (LF) or high (HF) abdominal fat. All birds were kept at constant high ambient temperature (32 C) and were provided with low- (LP) or high-protein (HP) diets from hatch until 8 wk of age (Experiment 1) or from 4 to 8 wk of age (Experiment 2). In both experiments, HP diet significantly increased 4- to 8-wk BW gain in the LF and HF stocks but reduced it in the WI stock as compared with the LP diet. Abdominal fat, as percentage of BW, was almost twofold higher in the HF birds than in the LF ones, with WI mean being intermediate. In contrast to the HF and WI birds, in which abdominal fat decreased with increased protein intake, abdominal fat was not affected by dietary protein in the LF stock. The HP diet substantially increased breast meat yield in LF birds but not in the WI birds, with HF birds exhibiting intermediate increase in breast meat weight. It was concluded that birds of varied inherent growth rate and tendencies toward protein and fat deposition respond differently to dietary protein level under heat stress.

Sulfur Amino Acid Requirement of Broiler Chicks from Fourteen to Thirty-Eight Days of Age.: 2. Economic Evaluation

A calculation model was developed that can be used to derive dietary methionine and cystine (TSAA) levels for maximum profitability in growing broilers. Based on dose-response curves from two broiler experiments, the model calculates additional income from improved feed conversion and from increased breast meat yield. From the comparison of additional income to the additional cost associated with increasing dietary TSAA levels, the TSAA content giving maximum profit can be estimated. Under European price conditions, a dietary level of .95% TSAA was found to be most profitable for broilers grown to 1.7 kg (Experiment 1, 14 to 34 d of age), when only the feed conversion response to dietary TSAA was considered. In broilers grown to 2.2 kg (Experiment 2, 14 to 38 d of age), two situations were simulated. If only the feed conversion response was evaluated, the most profitable TSAA level would be .85%. If both feed conversion and breast meat responses were considered, a higher level of .89% TSAA would be optimum. Changing prices of input and output variables (broiler feed, breast meat, DL-methionine) affected the respective economic optimum level of dietary TSAA only slightly.

Effect of Diet and Population Density on Male Turkeys Under Various Environmental Conditions.: 2. Body Composition and Meat Yield

Large White Nicholas male turkeys were reared at two stocking densities (.21 or .46 m2 per bird) and fed one of four diets: 1) control corn and soybean (mash) with 1% fat (CSM); 2) as Diet 1, pelleted (CSP); 3) as Diet 1 with supplemental fat increasing from 1 through 8% with age (CSF); and 4) as Diet 1 with barley at 0, 20, 35, 50, and 65% during successive 4-wk periods (CSB). The turkeys were reared in four environments: (A) intermittent light schedule [4(2 h light (L):4 h dark (D))] with temperature at 7 or 21 C during light and dark photoperiod, respectively; (B) and (D) with intermittent right (2L:4D) with a constant 21 and 7 C temperatures, respectively; (C) continuous light cycle (18L:6D) with temperatures as in Environment A.At 20 wk of age, two turkeys per replicate pen, were killed for determination of body composition and meat yield. Compared with turkeys fed CSM diet, those on CSF and CSP diet had increased percentage carcass fat. Meat yield per bird and percentage carcass fat were greater for turkeys reared at .46 m2 per bird compared with rearing at .21 m2 per bird. Pelleting and fat supplementation resulted in significantly increased amounts of breast meat and leg compared with CSM. Breast meat yield (percentage) and amount were greater at 7 C (Environment D) than at 21 C (Environment B) and the cycling regimen (Environment A). Percentage abdominal fat was greatest at 7 C.Interactions of environment and diet were detected for breast meat yield percentage (P<.023) and weight (P<.036). Diet type had no effect on percentage breast meat or wseight in Environment C. An increased amount of breast meat was obtained by feeding CSP in Environments A, B, and D, and dietary fat supplementation increased breast meat yield in Environments A and D over CSM treatment.