R. I. Bakalli

Dietary interrelationships among arginine, methionine, and lysine in young broiler chicks.

Since excess dietary lysine (Lys) can increase the chicks arginine (Arg) requirement and excess Arg can increase the chicks methionine (Met) requirement, experiments were conducted to test the hypothesis that responses to dietary Lys and Met are also interrelated. Day-old Ross x Ross chicks were fed a maize-soyabean meal-based diet supplemented with four levels of L-Arg (0, 5, 10 or 20 g/kg), factorially arranged with four levels of supplemental DL-Met (0, 1, 2 or 3 g/kg). Three replicate pens of ten chicks each were randomly assigned to each treatment and fed for 14 d. An increase in Arg in the diet caused growth and feed-intake depression (P=0.0001), but increasing Met in the diet enhanced growth and feed intake (P=0.0001). Arg toxicity was dependent on the Met level of the diet (Arg x Met interaction; P=0.0153). Experiment 2 was conducted to study interrelationships among Arg, Met, and Lys. Eight treatments were factorially combined: two levels of supplemental L-Arg (0 or 10 g/kg), two levels of supplemental DL-Met (0 or 2 g/kg), and two levels of supplemental L-Lys (0 or 6 g/kg). Six replicate pens of eight chicks per treatment were used. A three-way interaction among Arg, Met, and Lys was observed for body-weight gain and feed intake (P<0.023). As expected, kidney arginase activity increased as dietary Lys increased (P=0.0004). No interactions were found for kidney arginase activity. Muscle creatine increased when chicks were fed the higher Arg (25.2 g/kg) diet (P=0.0047). A three-way interaction among Arg, Met, and Lys was found for muscle creatine (P=0.0075). Excess dietary Lys depressed muscle creatinine concentration, but only in the presence of the lower concentrations of Arg and Met. To conclude, an interrelationship among Arg, Met, and Lys was demonstrated, and it was probably related to creatine biosynthesis.

Evaluation of corn distillers dried grains with solubles as an alternative ingredient for broilers

The effects of graded levels of corn distillers dried grains with solubles (DDGS) were investigated as a partial replacement for sources of protein, energy, and other nutrients for broilers when the digestible amino acid balance was maintained. Zero, 8, 16, and 24% DDGS were incorporated into isonutritive diets at the expense of corn, soybean meal, and dl-Met. Poultry oil, l-Lys, and l-Thr additions increased with increasing levels of DDGS. Diets were each fed to 36 Cobb 500 straight-run broilers in 6 floor pens in 2 experiments. In experiment 1, broilers fed ≥8% DDGS showed increased BW gain compared with those fed the control diet during the 0- to 18-d starter period (P = 0.0164) but were almost identical in BW at 42 d (P = 0.9395). The only difference at 42 d was in the carcass fat composition of female broilers: percentage of fat pad decreased with increasing DDGS level (P = 0.0133). Corn DDGS reduced the pellet durability index. However, the pellet durability index was not related to growth or feed utilization. In experiment 2 at 42 d, broilers fed all levels of DDGS showed increased BW gain compared with those fed the control diet. Broilers may perform well when fed properly balanced feeds containing up to 24% DDGS despite reduced pellet quality.

Chick responses to dietary arginine and methionine levels at different environmental temperatures

1. Two experiments were conducted with broiler chicks in battery brooders from 1 to 21 d to determine the broiler chicks’ responses to arginine (Arg) and methionine (Met) combinations at control (22 to 25°C) and warm (32 to 35°C) temperatures. 2. In Experiment 1, two levels of Arg (15·2 and 25·2 g/kg of the diet) and two levels of Met (3·5 and 5·5 g/kg) of a maize–soy based diet were fed at two temperatures, 22 or 32°C. Results of Experiment 1 were similar to those of Experiment 2, but most treatment differences were not significant. 3. In Experiment 2, chicks were randomly allotted to 9 dietary treatments: 3 levels of Arg (15·2, 25·2 and 35·2 g/kg of the diet) × 3 levels of Met (3·5, 5·5 and 7·5 g/kg of the diet) at 25 or 35°C. At the warmer temperature, chick growth depression from supplemental Arg was not as severe as at the control temperature (significant Arg × temperature interaction); neither were growth increases as large from supplemental Met (significant Met × temperature interaction). 4. Kidney and breast muscles were collected for arginase activity and creatine analysis, respectively. Remaining chicks were fasted for 10 h and re-fed. Excreta from the next 24 h were collected for total creatine and creatinine analysis. There were no effects of either Arg or Met on muscle creatine concentration at either control or warm temperatures. Chicks raised at 25°C excreted more creatine and creatinine than those raised at 35°C. 5. These results confirm that temperature affects responses to dietary Arg and Met and suggest that the higher temperature slowed the Arg metabolism of chicks through the creatine synthesis pathway.

The Effect of Breeder Age and Egg Storage Time on Phosphorus Utilization by Broiler Progeny Fed a Phosphorus Deficiency Diet with 1α-OH Vitamin D3

Two experiments were conducted to determine that variation in broiler P utilization is due to breeder age and egg storage time. Experiment 1 was conducted with chicks hatched from eggs laid by Ross x Ross 308 breeders (27 vs. 61 wk old) and stored for 0 or 10 d. The age of breeders had significant effects (P < 0.05) on 0 to 16 d chick growth (379 +/- 18 vs. 308 +/- 19 for 27- and 61-wk-old breeders, respectively). The longer egg storage time of chicks from older breeders resulted in higher P rickets scores and incidence, but longer egg storage time of chicks from younger breeders resulted in lower P rickets score and incidence (significant interaction, P = 0.0455). The longer egg storage time of chicks from older breeders resulted in lower bone ash (%), and the longer egg storage time of chicks from younger breeders resulted in higher bone ash (%). Experiment 2 was conducted with chicks hatched from eggs laid by Ross x Ross 308 breeders (26 vs. 60 wk old) and stored for 0 or 10 d. The diets were P deficient and with or without 5 microg/g of 1alpha-OH cholecalciferol (1alpha-OH vitamin D(3)). Breeder age had significant effects (P = 0.0003) on 0 to 16 d chick growth (272 +/- 7 vs. 339 +/- 8 for 26- and 60-wk-old breeders, respectively) and chick mortality (P = 0.0134). The P rickets score increased with breeder age (P = 0.0186) and egg storage time (P = 0.1057). The factors influencing the incidence of P rickets in broilers should include breeder age and egg storage time as well as genetics and dietary levels of Ca, P, and vitamin D activity of the P-deficient diets.

{Delta}-Aminolevulinic acid dehydratase: A sensitive indicator of lead exposure in broiler chicks: (Gallus domesticus)

Delta-aminolevulinic acid dehydratase, EC 4.2.1.24 (ALAD) is one of the enzymes participating in heme synthesis. The study reported in this paper was designed to determine the activity of erythrocyte ALAD anbd the relationship between this enzyme and tissue lead levels in chickens, during Pb intake and after withdrawing Bv from the feed. 20 refs., 3 tabs.