Cellular and Biochemical Aspects of Fat Deposition in the Broiler Chicken

Effect of Dietary Bacillus coagulans and Different Forms of Zinc on Performance, Intestinal Microbiota, Carcass and Meat Quality of Broiler Chickens

A total of 288-day-old male broilers were allocated to six dietary treatments to evaluate the effects of zinc source and Bacillus coagulans supplements and their interaction on growth, intestinal microbial population, carcass traits and meat quality in broiler chickens. Three levels of dietary supplemental Zn source (100 mg/kg of DM diet zinc oxide, 25 and 50 mg/kg of diet zinc oxide nanoparticles (Zn-nan)) and two levels of B. coagulans (0 and 100 mg/kg of diet) were combined as a completely randomised design with a 3 × 2 factorial arrangement. B. coagulans increased the body weight gain, body weight and feed conversion ratio. The lactic acid producing bactereia of ileal were increased by B. coagulans supplementation, and its coliform count was decreased by Zn-nan in a dose-dependent manner. The B. coagulans increased the relative weights of legs and proventriculus and reduced weights of livers, abdominal fat and meat thiobarbituric acid (TBA) value. Likewise, dietary B. coagulans increased pH, yellowness and lightness values of leg muscles. Birds fed Zn-nan50 had lower liver weight, TBA and cooking loss and higher yellowness values than chicks fed ZnO-100. In conclusion, the dietary supplementation with B. coagulans improved broiler performance, microbial population and meat quality. The Zn-nan in lower dose could be a good substitution in mineral premix instead of zinc oxide. In addition, the Zn-nan improved intestinal microbial population, carcass characteristics and oxidative stability of chicken meat; however, the combination of two levels of Zn-nan with B. coagulans did not vary the measured parameters.

Chemical composition of muscle after pollen application in nutrition of broiler chickens

Principle purpose of this study was to monitor the chemical composition of breast and thigh muscular part of chickens of hybrid combination Ross 308 and to verify the differences due to use of pollen extract in feed mixture at a dose of 400 and 800 mg.kg-1 during the feeding of 42 days. We did not find significant differences (P≥0.05) in followed chemical compounds of thigh muscle with the skin and subcutaneous fat between the groups with and without application of pollen extract: in contents of water (68.49-70.12 g.100g-1), protein (18.82-18.98 g.100g-1), fat (9.96-11.53 g.100g-1) and in energy value (692.20-752.36 kJ.100g-1). Significant differences (P≤0.05) were found only in protein content of breast muscle between the control group (23.96 g.100g-1) and experimental group I (23.28 g.100g-1). Values of water content (73.97-74.32 g.100g-1), fat content (1.07-1.40 g.100g-1) and energy (441.65-446.64 kJ.100g-1) in breast muscle between the evaluated groups were balanced (P≥0.05). The results show that pollen extract at the concentration used in feed mixture did not effect basic chemical composition of the most valuable parts of the chicken Ross 308 carcass and we can apply it in their nutrition. Application at a dose of 800 mg.kg-1 seems to be more positive.

Dietary fatty acid profile modifies abdominal fat deposition in broiler chickens

An experiment was conducted to study the effect of different dietary fatty acid profiles on abdominal fat deposition in broilers. Diets with four types of fats (tallow, olive oil, sunflower oil, and linseed oil), at two levels of fat inclusion (either 6 or 10%), were administered to males from 21 to 42 d and to females from 21 to 49 d of age. The sexes were studied separately. Performance parameters, abdominal fat, muscle fat and cholesterol, and fatty acid profile of thigh, breast, and abdominal fat were determined. Broilers fed sunflower and linseed oils presented better values of feed efficiency. Abdominal fat and cholesterol content of thigh muscle were significantly lower in animals fed sunflower and linseed oils than in those fed tallow or olive oil (P < 0.001). In females, abdominal fat increased with level of fat inclusion only in birds fed tallow or olive oil, whereas it remained constant in birds fed sunflower or linseed oil. Muscle fat content was lower for birds fed tallow or olive oil but not significantly. The fatty acid profile of the different tissues reflected dietary fatty acid profile. Monounsaturated fatty acids were higher in abdominal fat, whereas polyunsaturated fatty acids were higher in muscle fat. These results suggest that polyunsaturated fatty acids produce lower abdominal fat deposition than saturated or monounsaturated fatty acids.

Effect of full feed and early feed restriction on broiler performance, abdominal fat level, cellularity, and fat metabolism in broiler chickens

Three hundred sixty Peterson x Arbor Acres chicks were fed two feed regimens to compare their effects on adipose cellularity, adipocyte lipolysis, hepatic glucose oxidation, adipocyte lipogenesis, bird performance, and abdominal fat level. Broilers in the first regimen had ad libitum access to feed throughout the 7-wk experiment, whereas broilers in the second regimen consumed feed at will throughout the experiment except that they were subjected to feed restriction (1.49 kcal/g BW2/3 daily) from 7 to 12 d of age (DOA). No differences in mean body weights were observed between the full-fed and restricted males and combined sex broilers at 49 DOA. Feed conversion and abdominal fat levels of female and combined sex were lower (P < .05) for the restricted than full-fed broilers. No differences in adipocyte numbers based either on whole abdominal fat pads at 28 and 42 DOA or per gram fat at 42 DOA were observed between broilers fed the two feed regimens. However, the adipocyte numbers per gram fat at 28 DOA were greater (P < .05) for the restricted broiler than for the broilers that ate freely. Lipolysis based per million adipocytes was not different between the treatments at 28 and 42 DOA; however, lipolysis based on per gram adipose tissue was increased (P < .05) with the addition of isoproterenol and theophylline for the restricted broilers compared to the full-fed broilers at 28 DOA. No difference was observed between the feed regimens at 42 DOA with hormone addition. Lipogenesis of the restricted broilers was lower (P < .05) than that of the full-fed broilers at 14 and 56 DOA. No difference in glucose oxidation was found between chickens fed the two regimens. Reduced abdominal fat in the restricted broilers is attributed to the reduction of adipocyte volume, which may be due to decreased lipogenesis.

Rapidly growing broiler (meat-type) chickens: their origin and use for comparative studies of the regulation of growth

1. Rapidly growing (meat-type) chickens have been intensively selected for over 50 years and grow up to four times faster than "layer" strains selected for reproductive traits. 2. Comparison between these lines are increasingly being used to study mechanisms underlying lean tissue growth. 3. Selection for increased growth has resulted in some undesirable consequences such as poor reproductive performance, excessive fatness, increased skeletal abnormalities and ascites. 4. The biochemistry, physiology and molecular biology of these changes are reviewed.

Comparison of the rates of proliferation of adipocyte precursor cells derived from two lines of chicken which differ in their rates of adipose tissue development

1. Putative adipocyte precursor cells were isolated from the white adipose tissue of young broiler and layer chickens and cultured in vitro. 2. The cells from both sources were shown to have the characteristics of adipocyte precursor cells. On reaching confluence, lipoprotein lipase activity was induced and the cells from both strains accumulated large amounts of lipid in the presence of chicken serum. 3. Measurement of cell number over time in culture and calculation of cell doubling times showed that cells from broilers proliferated at a faster rate than those derived from layer-strain chickens. This was the case whether primary or secondary cell cultures were used. Primary cultures of broiler cells had a doubling time of 22 h versus 39 h for layer cells. 4. The contribution of such a difference in proliferative rate to the differential rate of adipose tissue growth between broiler and layer strains observed in vivo is discussed.

Cytotoxic antibodies to chicken adipocytes and their precursors: lack of tissue specificity

1. Antisera raised in sheep against chicken adipocyte plasma membranes recognised adipocyte, liver and red blood cell membranes in enzyme immunoassays (EIA). 2. These antisera were cytotoxic when incubated with both adipocytes and their precursors grown in culture, and with red blood cells. 3. Adsorption of antisera with liver membranes completely abolished the response to liver and red blood cell membranes in the EIA. The response in adipocytes was reduced to only about 6% of the titre present in the unadsorbed sample. 4. Adsorption of antisera with liver membranes abolished the cytotoxic response to red blood cells and to adipocyte precursors, but some response to adipocytes still remained. 5. These results are in contrast to the rat for which adipocyte specific antisera were obtained which represented about 75% of the unadsorbed titre.

Effects of dietary biotin and linoleate on polyunsaturated fatty acids in tissue phospholipids

Two experiments with factorial designs were conducted to study the interaction between dietary biotin and linoleate in male broiler chicks. Chicks were fed a purified basal diet containing varying levels of d-biotin (0, 200, or 400 micrograms/kg diet) and linoleate. In Experiment 1, chicks were fed the basal diet containing three levels of added linoleate (.5, 3.1, or 4.1% of diet) for each biotin level and in Experiment 2, four levels of linoleate were fed (.27, .98, 2.00, or 2.20% of diet). The average body weights of chicks fed biotin at 200 micrograms/kg of diet and .27 or .5% added linoleate were not different (P greater than .05) from those of chicks fed higher levels of biotin or linoleate supplements to the basal diets. Linoleate deficiency resulted in elevated omega-9 fatty acids (18:1 omega 9 and 20:3 omega 9) in liver and heart phospholipids. For liver phospholipids, linoleate deficiency led to reduced 18:2 omega 6, 20:3 omega 6, and 20:4 omega 6 but for heart phospholipids only 20:4 omega 6 was lowered. Biotin deficiency resulted in elevated 18:3 omega 6 in liver and heart lipids and decreased 20:3 omega 6 in liver phospholipids. Liver microsomes from biotin-deficient chicks contained increased 18:2 omega 6 and reduced 20:3 omega 6 compared with those of biotin-adequate chicks.