THE USE OF EARLY-AGE FEED RESTRICTION ANDIOR POTASSIUM CHLORIDE FOR ALLEVIATING THE ADVERSE EFFECTS OF HEAT STRESS ON BROILER CHICKS: 2- EFFECTS ON SOME PHYSIOLOGICAL PARAMETERS, BLOOD CONSTITUENTS And Digestibility Of Nutrients. | ||||
| Journal of Animal and Poultry Production | ||||
| Article 17, Volume 28, Issue 1, January 2003, Page 293-313 PDF (6.95 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2003.242202 | ||||
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| Authors | ||||
| A. H. Raya,; Kh. EI. Sherif; Tork M. Dorra; Z. M. Kalaba | ||||
| Department of Poultry Production, Faculty of Agriculture, Mansoura University, Egypt. | ||||
| Abstract | ||||
| The present study was carried out to investigate the possibility of alleviating the adverse effects of heat stress to which broiler chicks are exposed during the summer season by means of early-age feed restriction (EFR) and/or dietary supplementation with potassium chloride (KCI). Three hundred and sixty, one-day-old, broiler-type Hubbard chicks were randomly divided into two halves, each of which was assigned to four treatments (T), and given starter diets from 1 to 21 days of age, then, the birds were switched to grower diets from 22 to 42 days of age. Two feeding regimens were imposed on these birds. Chicks of the first half (T1, T2, T3 and T 4) were full-fed (FF), during the entire experimental period from 0 to 6 weeks of age, while birds of the other half (T5, T6, T7 and T8) were subjected to feed restriction; only during the first week of life. Each of the starter and grower diets were isocaloric and isonitrogenous, and originally contained about 0.8% K. Diets of T1 and T5 were unsupplemented with KCI and served as controls, while diets for chicks of T2 and T6, T3 and T7 or T4 and T8, were supplemented with KCI at levels of 0.75, 1.5 and 2.25%, respectively. Thus, in these diets supplemental KCI plus basal K provided dietary K levels of 0.8, 1.2, 1.6 or 2.0%, respectively. The criteria of response were some physiological changes, levels of some blood constituents and nutrients digestibility. The obtained results can be summarized as follows: Early-age feed restriction (during the first week) of broiler chicks decreased significantly (P::;0.01) body temperature, panting rate, blood pH and sedimentation rate, and plasma corticosterone (P::;0.05), but increased (P::;0.01) the activity of alkaline phosphatase and plasma concentrations of k and T3. However, blood hemoglobin, concentrations of plasma total protein, total lipids, glucose, cholesterol, Na, CI, and T4 were not affected. Supplemental KCI decreased significantly (P::;0.01) body temperature, panting rate, and blood pH and sedimentation rate, but increased (P::;0.01) the activity of alkaline phosphatase, and the concentrations of plasma total protein, Na, K, T3 and T4. However, blood hemoglobin, and plasma concentrations of total lipids, glucose, cholesterol, CI and corticosterone were not affected. Early-age feed restriction did not affect digestibility of crude fiber (CF), organic matter (OM), ether extract (EE), nitrogen free extract (NFE), nitrogen retention, ash retention, or k retention, but decreased dry matter (OM) and crude protein (CP) digestibility. Supplemental KCI did not affect nitrogen retention and the digestibility of CF or NFE, but the high level (2.25%) improved the digestibility of OM, OM, EE, and CP and ash and K retention. The use of early-age feed restriction with 2.25% dietary KCI level for broiler chicks in hot climate during the summer season was recommended. | ||||
| Keywords | ||||
| Broiler chicks; physiological parameters; early-age feed restriction; dietary KC)' | ||||
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