ABSTRACT
Published equations for estimating the daily energy needs of laying hens were combined with published equations for estimating the daily amino acid needs to derive estimated energy:amino acid ratios for laying hens at different stages of production and environmental temperatures. Two feeding trials were conducted using various percentages of the suggested ratios to determine their applicability. The results of these studies indicate that the calculated energy:amino acid ratios appeared to support production levels comparable with those of hens fed higher nutrient levels. The use of temperature-adjusted energy:amino acid ratios appears to be a valid and feasible means of formulating diets to meet the changing nutritional needs of laying hens.
Subject(s)
Amino Acids/metabolism , Chickens/physiology , Energy Metabolism , Oviposition , Age Factors , Animals , Body Weight , Female , Models, Biological , Nutritional Requirements , TemperatureABSTRACT
Three experiments were conducted to compare different methods of short-term potentiation of tetracycline antibiotics for broiler chicks. Reduction of dietary calcium and addition to sodium sulfate were compared in different combinations with various levels of chlortetracycline (CTC) and oxytetracycline (OTC). Reducing dietary calcium from 0.8 to 0.4% significantly increased serum levels of CTC and OTC. Adding sodium sulfate (1.25%) also increased serum levels; the majority of the response occurred at the higher calcium level. There was no benefit from adding sodium sulfate to the low-calcium diet. Neither body weight gain nor feed utilization were adversely affected during the 5-day test period.
Subject(s)
Calcium, Dietary/pharmacology , Chickens , Chlortetracycline/pharmacology , Oxytetracycline/pharmacology , Sulfates/pharmacology , Animals , Body Weight/drug effects , Calcium, Dietary/administration & dosage , Chickens/blood , Chlortetracycline/blood , Diet , Drug Synergism , Female , Male , Oxytetracycline/blood , Sodium/administration & dosage , Sodium/pharmacology , Sulfates/administration & dosageABSTRACT
Two consecutive trials were conducted with male Large White turkeys grown from day-old to 20 weeks of age on diets formulated to contain 0, 2, 4, 6, and 8% fat with constant amino acid energy ratios. The addition of 2 and 4% fat significantly improved body weight gain; higher levels gave no further improvement. Feed conversion efficiency was improved by the addition of fat to the diet, but caloric efficiency remained relatively constant over the range of energy levels, indicating that there was not "extra-caloric" effect of fat observed in this study. Possible contributions of methods of feed formulation toward the possibility of the occurrence of this phenomenon are discussed.
Subject(s)
Animal Feed , Energy Metabolism , Turkeys/physiology , Animals , Dietary Fats/metabolism , Turkeys/growth & development , Turkeys/metabolismABSTRACT
A liquid methionine supplement known as methionine hydroxy analogue-free acid (MHA-FA) was evaluated as a source of methionine in the diet of young broiler chicks. Diets calculated to be deficient in methionine were supplemented with MHA-FA and performance compared to that obtained when comparable diets were supplemented with molar equivalents of methionine from L-methionine, DL-methionine, or the calcium salt of methionine hydroxy analogue. Performance of chicks fed the test product was equal to that obtained on the other methionine products. The use of MHA-FA might allow for a more even distribution in the diet, easier handling, and a lower manufacturing cost with resultant savings in the cost of producing poultry and eggs.
