scholarly journals Effects of Varying Dietary Protein and Energy Levels on Growth Rate and Body Fat of Broilers

1980 ◽  
Vol 59 (7) ◽  
pp. 1499-1504 ◽  
Author(s):  
PHILLIP H. HARGIS ◽  
C.R. CREGER
1972 ◽  
Vol 52 (1) ◽  
pp. 87-96 ◽  
Author(s):  
J. F. O’GRADY ◽  
J. P. BOWLAND

One hundred and sixty pigs weaned at 2 weeks were allotted at an average initial weight of 3.8 kg to two experiments to examine the effects of diets based on barley or wheat as the cereal component and having digestible energy (DE) concentrations ranging from 2.8 to 3.6 Mcal/kg. Protein was in constant ratio to DE (15.2 kcal DE/g protein). Very high mortality was experienced on the lower energy levels, although the inclusion of 5% molasses in the formulation reduced mortality. Among surviving pigs, growth rate was significantly reduced at lower energy concentrations. The optimum DE level for maximum gain was 3.2 Mcal in the first experiment and 3.4 Mcal/kg in the second. The efficiency of utilization of DE for growth was best at a DE concentration of 3.2 Mcal/kg in the first experiment but did not vary in the second. Digestibility of dietary protein increased with increasing dietary DE but nitrogen (N) retention as percentage of N intake or of digestible N was not significantly influenced by DE in the diet.


1962 ◽  
Vol 26 (10) ◽  
pp. 640-647 ◽  
Author(s):  
Minoru YOSHIDA ◽  
Sadanobu HIZIKURO ◽  
Hiroshi HOSHII ◽  
Hiroshi MORIMOTO

1962 ◽  
Vol 26 (10) ◽  
pp. 640-647
Author(s):  
Minoru Yoshida ◽  
Sadanobu Hizikuro ◽  
Hiroshi Hoshii ◽  
Hiroshi Morimoto

1975 ◽  
Vol 34 (3) ◽  
pp. 363-373 ◽  
Author(s):  
E. Wetnli ◽  
T. R. Morris ◽  
T. P. Shresta

1. Three growth trials were done using male broiler chicks. In the first two trials, groundnut meal was used, with and without supplementary methionine and lysine. In the third trial, soya-bean meal was used with and without supplementary methionine. Protein levels ranged in the first trial from 120 to 420 g/kg diet and in the third trial from 120 to 300 g/kg diet. Thus the assumed minimal amino acid requirements of the chick were supplied by high levels of low-quality dietary protein.2. Diets based on cereals and groundnut meal did not support maximum live-weight gain or maximum efficiency of food utilization at any level of dietary protein. When the principal deficiencies of lysine and methionine were corrected, this protein mixture was capable of supporting the same growth rate as a control diet of cereals and herring meal.3. Diets based on maize and soya-bean meal did not support quite the same growth rate as similar diets supplemented with methionine, even though the protein level in the unsupplemented diets was sufficient to meet the assumed methionine requirements.4. These results are interpreted as examples of amino acid imbalance in diets composed of familiar feeding-stuffs. It is concluded that one cannot assume that the poor quality of a protein source can always be offset by increasing the concentration of dietary protein.


2013 ◽  
Vol 48 (6) ◽  
pp. 645-650 ◽  
Author(s):  
Cleujosí da Silva Nunes ◽  
Gilberto Moraes ◽  
Fernando Fabrizzi ◽  
Araceli Hackbarth ◽  
Gustavo Alberto Arbeláez-Rojas

The objective of this work was to evaluate the effect of sustained swimming and dietary protein levels on growth and hematological responses of juvenile pacu (Piaractus mesopotamicus). A completely randomized design was used in a 3x2 factorial arrangement, with three levels of dietary protein (24, 28, and 32% crude protein), two rearing conditions (sustained swimming or motionless water), and 15 replicates. Fish were subjected to sustained swimming at the velocity of two body lengths per second (2 BL s-1), for 45 days. The level of dietary protein and the swimming conditions affected the performance, growth, and hematological profile of pacu. Swimming conditions influenced nutritional factors, increasing daily weight gain, specific growth rate, number of erythrocytes, mean corpuscular volume, and mean corpuscular hemoglobin. Fish under sustained swimming and fed with 24% crude protein showed better growth performance, with higher specific growth rate (4.11±0.88) and higher daily weight gain (2.19±0.47 g per day). Sustained swimming can increase the productive performance of pacu and simultaneously reduce dietary protein levels.


1987 ◽  
Vol 44 (11) ◽  
pp. 1995-2001 ◽  
Author(s):  
Stephen H. Bowen

It is widely believed that fishes require more dietary protein than other vertebrates. Many aspects of fish physiology, nutrition, and trophic ecology have been interpreted within the context of this high protein requirement. Here, fishes are compared with terrestrial homeotherms in terms of (1) protein requirement for maintenance, (2) relative protein concentration in the diet required for maximum growth rate, (3) protein intake rate required for maximum growth rate, (4) efficiency of protein retention in growth, and (5) weight of growth achieved per weight of protein ingested. The two animal groups compared differ only in relative protein concentration in the diet required for maximum growth rate. This difference is explained in terms of homeotherms' greater requirement for energy and does not reflect absolute differences in protein requirement. The remaining measures of protein requirement suggest that fishes and terrestrial homeotherms are remarkably similar in their use of protein as a nutritional resource. Reinterpretation of the role of protein in fish physiology, nutrition, and trophic ecology is perhaps in order.


1996 ◽  
Vol 75 (2) ◽  
pp. 237-248 ◽  
Author(s):  
Christiani Jeyakumar Henry ◽  
Amal Ghusain-Choueiri ◽  
Philip R. Payne

AbstractThe relationship between essential fatty acids (EFA) deficiency and the utilization of dietary protein, growth rate and survival of offspring was investigated in rats during development and reproduction. EFA deficiency was induced by feeding a 200 g casein/kg-based diet containing 70 g hydrogenated coconut oil (HCO)/lkg as the only source of fat. The conversion efficiency of dietary protein was assessed as net protein utilization (NPU), using a 10 d comparative carcass technique. Consumption of the deficient diet during the 10 d assay period induced biochemical changes characteristic of mild EFA deficiency in humans (triene:tetraene 0·27 (SD 0·04) compared with 0·026 (SD 0·004) for wn-deficient controls), but there were no significant changes in growth rate or protein utilization. These variables were also unchanged when the deficient diet was fed for an additional 7 d before the assay, although triene: tetraene increased to 0.8 (SD 0·02). Feeding the deficient diet for 63 d before assay produced severe EFA deficiency (triene:tetraene 1.4 (SD 0·3) v. 0·036 (SD 0·005) for controls), a fall in growth rate (25% during assay period), and NPU (31.5 (SD 0·63) v. 39.0 (SD 0·93) for controls). These severely-EFA-deficient animals had a 30% higher fasting-resting rate of energy metabolism than that of age-matched controls. However, there was no change in the rate of endogenous N loss. Voluntary energy consumption was increased in animals fed on deficient diets, either with 200 g protein/kg, or protein free. The reduced efficiency of protein utilization could be entirely accounted for by the restricted amount of energy available for growth and protein deposition. Consumption of an EFA-deficient diet during pregnancy and lactation resulted in high mortality (11% survival rate at weaning compared with 79% for controls) and retarded growth in the preweaning offspring. It is concluded that animals are particularly sensitive to EFA deficiency during reproduction and pre- and post-natal stages of development. However, after weaning only severe EFA deficiency retarded growth, primarily through changes in energy balance.


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