Effects of different protein and energy contents of the diet on growth performance and hormonal parameters in two commercial broiler strains (original) (raw)
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Italian Journal of Animal Science, 2010
We studied the effects of different energy and protein contents of the diet on performance, growth hormone concentration and ghrelin gene expression in broiler chicken. Two experiments were conducted to determine whether different dietary energy and protein levels alter growth hormone concentration and ghrelin mRNA abundance in broiler chicks. Body weight and feed intake were recorded weekly. Blood, carcass traits and proventriculus samples were collected at 21, 42 and 56 days of age. Blood samples assayed for growth hormone (GH) concentration by radio immuno assay (RIA) and ghrelin gene expression from proventriculus tissue was measured by Real Time polymerase chain reaction (PCR). Feed intake and body weight gain increased in broilers fed on low-energy diets compared with those fed on high-energy diets at 21 days of age (P<0.0001). Also, increasing dietary energy improved feed conversion (FCR) at 22-42 days of age in broiler chicken (P<0.0001). Increasing levels of protein increased feed intake, body weight gain and improved FCR as compared with low level of protein. Carcass percentage and breast percentage increased in broilers fed on high protein diets compared with those fed on low-protein diets during different periods. High-energy and low-protein diets increased abdominal fat percentage in broiler chickens. The result of this experiment indicated that there was no effect of different dietary energy and protein levels on growth hormone concentration and ghrelin gene mRNA expression for broiler chicken.
British Journal of Nutrition, 1998
Indian River male broiler chickens growing from 7 to 28 d of age were fed on diets containing either 120 or 210 g crude protein and 0 or 1 mg triiodothyronine (T3)/kg diet to studyin vitrolipogenesis (IVL). In addition, a carry-over period (180 g crude protein/kg diet from 28 to 40 d of age) was used to test the persistence of prior treatment effects. The higher protein level increased, but T3decreased (P< 0.01) growth and feed consumption at 28 d of age. The lower protein level increased (P< 0.05) and T3decreased IVL in 28-d-old chickens. These effects were only sustained for 6 d following the switch to a common diet at 28 d. IVL at 40 d of age was not affected by either crude protein or T3fed during the 7–28 d period. The higher protein level increased plasma insulin-like growth factor-1 during the period from 7 to 28 d; however, this effect lasted for only 6 d following the switch to a common diet. Plasma growth hormone (GH) at 28 d of age was inversely related to dietary p...
General and Comparative Endocrinology, 1997
Plasma concentrations of metabolic hormones were determined in broiler breeders fed on three quantitatively different food regimes in the period prior to sexual maturity. The first group was fed ad libitum, the second group was fed a restricted quantity of food, and the third group was restricted to obtain an intermediate body weight between those of the first two groups. In foodrestricted birds, insulin-like growth factor-I (IGF-I) reached the highest plasma concentrations at 8 and 14 weeks of age in contrast with levels in the fully fed animals, in which only one maximum value was observed at 10 weeks. From 14 weeks on, IGF-I concentrations remained higher in the restricted groups compared to the ad libitum group. Three IGF-binding proteins with molecular masses of 28, 34, and 40.5 kDa were detected in the plasma of broiler breeders after Western ligand blotting. The concentrations of the 28-and 34-kDa IGF-binding protein bands showed an age-related pattern in all groups. The intensity of these bands was higher in the restricted groups compared to that of the bands for the fully fed animals. No significant differences between the groups could be observed in the intensity of the 40.5-kDa band. Food restriction resulted in higher plasma concentrations of GH and T 4 compared with levels in the fully fed animals. T 3 plasma concentrations were higher in the ad libitum fed group than in the restricted groups. In all groups, GH and T 3 concentrations decreased with advancing age, whereas T 4 increased during the same period. This is the first description of the effects of long-term food restriction prior to the onset of sexual maturity on circulating levels of hormones of the somatotrophic and the thyrotrophic axes in female broiler breeders. The interrelationship between GH, IGF-I, IGFBPs, and thyroid hormone concentrations and differences in subsequent reproductive performance of differently fed broiler breeders requires further investigation. r 1997 Academic Press
British Poultry Science, 1992
1. The effect of the crude protein content (200 and 150 g/kg) of isoenergetic diets on episodic growth hormone (GH) release and on heat production was investigated in male broiler chickens. 2. Decreasing the crude protein content of isoenergetic diets from 200 g/kg (HP diet) to 150 g/kg (LP diet) resulted in depressed body weight gain, impaired food conversion efficiency and increased abdominal fat deposition. 3. The pattern of growth hormone secretion was markedly affected by dietary treatment. Broiler chickens fed on the LP diet had higher overall mean, amplitude, baseline and peak frequency than the HP chickens. 4. The LP chickens produced more heat per unit of metabolic body weight than the HP chickens. 5. The hypothesis relating the pattern of GH secretion to protein conversion efficiency was corroborated.
Implications of dietary macronutrients for growth and metabolism in broiler chickens
World's Poultry Science Journal, 2007
In chickens, metabolism is influenced by environmental factors and of particular interest nutritional factors, such as diet quantity and composition. With respect to the dietary macronutrients, literature clearly shows that in isoenergetically formulated diets, the protein level has a pronounced effect on metabolism, whereas fat and carbohydrate concentrations play a limited role. A decreased dietary protein level results in depressed growth rates, with reduced carcass gains in both water and protein content. In spite of the lower protein retention in chickens fed low protein diets, the efficiency of utilization of dietary protein appears to be increased. This indicates an inverse relationship between protein intake and utilization, which is reflected in decreased circulating uric acid levels. In addition, feed intake is increased, at least when protein levels are slightly reduced, leading to an involuntary overconsumption of energy compared to protein. The chickens deal with this excess energy consumption by increasing de novo lipogenesis and fat deposition, which is supported by increased plasma triglyceride concentrations, and heat production is increased. In contrast to adult mammals, the dietary macronutrients have no effect on diet-induced thermogenesis, nor is there any relationship between diet-induced thermogenesis and feed intake. Plasma growth hormone levels are higher in chickens reared on a low protein diet, indicating a causal relationship between growth hormone secretion and protein efficiency. In spite of the increased growth hormone levels, plasma insulin-like growth factor concentrations are lowered in low protein reared chickens, and may be partially responsible for the reduced growth rate observed in these animals. Plasma corticosterone concentrations are augmented in chickens on low protein diets, despite a decline in the ACTH concentration. Finally, plasma T 3 and T 4 levels are well known to increase and decrease, respectively, with decreasing protein content, whereas the effects of dietary macronutrients on circulating leptin levels require more research.
Poultry Science, 2008
A trial was conducted to determine the effects of different feeding regimens on plasma hormone and metabolite levels in 16-wk-old broiler breeder pullets. A flock of 350 Cobb 500 breeder pullets was divided in 2 at 28 d of age and fed either every day (ED, 5 pens of 35 birds) or skip-a-day (SKIP, 5 pens of 35 birds) from 28 to 112 d of age. Total feed intake did not differ between the 2 groups. At 112 d, 52 randomly selected pullets from the larger flock of ED-fed pullets, and 76 from the SKIPfed pullets were individually caged and fed a meal of 74 g (ED) or 148 g (SKIP). Blood samples were collected from 4 pullets in each group by cardiac puncture at intervals after feeding. Plasma was analyzed for insulin, glucagon, insulin-like growth factor-I and insulin-like growth factor-II, triiodothyronine and thyroxine, corticosterone, leptin, glucose, nonesterified fatty acids, triglycerides, and uric acid. Feed retention in the crop was also noted
IOSR Journals , 2019
Poultry development plays a crucial role in increasing egg and chicken meat production. Poultry rearing provides income and employment to large number of people. The objective of this investigation is to determine the performance of broiler chicken when fed with diets containing different combinations of energy and protein. Total of 200 (day-old chicken) broiler chickens of a commercial strain randomly selected for three different experiments and feeding with experimental rations. The birds rearing period was 6 weeks, the live body weight performance and health condition were measured by weekly. For each experiment Eighty (80) 1-day-old male broiler chickens of a commercial strain were selected in four groups with control including supplements diet treatments. Each treatment group of 20 birds was allocated. In the first and second weeks of feeding the body weight of broiler chicken was significantly increased by corn (starch rich supplements), however the body weight in week 4 and 5 was significantly increased by protein supplements particularly alfalfa. Also feed additives had significantly effect on growth performance where mortality rate was zero.
Reproduction Nutrition Development, 1992
The aim of the present experiment was to study the growth hormone (GH) response upon thyrotropin releasing hormone (TRH) challenge (2 µg/kg body weight) in broiler chickens selected for body weight gain (GL line: fat line) or for feed efficiency (FC line: lean line) reared at either a moderate (33-23°C) or high (33°C) ambient temperature. A higher plasma GH level at 5 min after TRH administration was observed in the high temperature conditioned chickens of both lines. Also at high ambient temperature, an enhanced GH decrease between 15 min and 30 min post-injection and a higher acute elimination rate was calculated compared to moderate ambient temperature. A significantly higher GH secretory response was observed in the leaner FC line chickens, which was probably related to the more pronounced pulsatory GH secretion rate in these chickens. There was no difference in GH acute elimination rate between both lines in both environments. No interactions between line and rearing temperature for these parameters of GH dynamics were observed.
Comparative biochemistry and physiology. A, Comparative physiology, 1987
The effects of dietary triiodothyronine (T3), injections of a preparation of growth hormone (GH) (purified from chicken pituitary tissue) and their combination on growth were investigated in three lines of chickens. The three lines were the Cornell K strain (K) (a single Comb White Leghorn strain), the Cornell K strain hemizygous for the sex-linked dwarfing gene (SLD), and the Cornell K strain homozygous recessive for the autosomal dwarfing gene (ADW). A dietary T3 treatment by genotype interaction was observed. Dietary T3 (0.1 ppm) decreased growth in the K line, tended to decrease growth in the ADW line while it tended to increase growth in the SLD line. Chicken growth hormone (100 micrograms/kg body wt) alone did not affect growth in any of the lines studied. There was, however, a GH treatment by T3 treatment interaction. Chicken GH overcame the growth-depressing effects of T3 in the K and ADW lines while it tended to promote growth in T3 treated SLD birds. Dwarf (SLD) chickens h...