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

Abstract

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.

Acknowledgement

Supported by state and Hatch funds allocated to the Georgia Agricultural Stations of the University of Georgia.

Notes

¹Values as means ± standard errors of n replicate pens of 8 birds each.

²Pooled standard error (root mean square error /).

³An error term to determine temperature effect.

Significant dietary Arg by Met concentrations were detected for feed, Arg and Met intakes (P ≤ 0·05) and nearly significant for feed conversion efficiency (P = 0·075).

Met by temperature interactions were nearly significant for feed and Arg intakes, body gain and feed conversion efficiency (P < 0·063).

¹Values as means ± standard errors of n replicate pens of 8 birds each.

²Pooled standard error (root mean square error/.

Significant dietary Arg concentration by temperature and Met concentration by temperature interactions were detected for feed, Arg and Met intakes and body weight gain, and Met by temperature (P = 0·04) and Arg by temperature (P = 0·09) for feed conversion efficiency. The Arg by Met by temperature interaction only approached significance for body weight gain (P = 0·067).

¹Values as means of n replicate samples of two birds each.

²Values as means of n replicate samples of 4 to 6 birds each.

³Pooled standard error (root mean square error/().

Significant effects were detected for dietary Arg concentration (P < 0·01) and Arg by temperature (P = 0·061) for kidney arginase activity, and Arg by Met and Arg by temperature for total excreta creatine and creatinine (P < 0·001).

¹Variables left out of all models because they were not significant at the 0·10 level included Met × Met, Arg intake × Arg intake, and Met intake × Met intake.