Contribution of lipoprotein lipase to differences in fatness between broiler and layer-strain chickens

The growth of abdominal fat in chickens from broiler and layer-strains up to 10 weeks of age was measured and compared with changes in plasma very low density lipoprotein (VLDL) concentration and tissue lipoprotein lipase activities. The growth of abdominal fat in broilers was much more rapid than in layer-strain chickens. Plasma VLDL concentrations in the two strains were similar up to 5 weeks of age but thereafter concentrations tended to be higher in broilers. Plasma VLDL concentrations in both strains were much lower than those necessary for maximum lipoprotein lipase activity. The lipoprotein lipase activity of abdominal fat increased much more rapidly in broilers than in layer-strain chickens. In both strains the pattern of its increase relative to body weight was similar to that of abdominal fat. Differences in the lipoprotein lipase activity of abdominal fat between strains were attributed to differences in both activity/adipocyte and number of adipocytes. They were reduced or abolished if activity was expressed relative to tissue weight, or to its content of DNA or protein. The results strongly suggest that the greater lipoprotein lipase activity of the abdominal fat pad in broilers is an important factor in its rapid growth.     

Effect of Escherichia coli endotoxin on tissue lipoprotein lipase activities in chickens

1. Four-week-old broiler chickens were injected intravenously with from 0.01 to 1 mg of E. coli endotoxin/kg body weight or with saline. 2. At all doses used endotoxin markedly depressed food intake and lipoprotein lipase activities in muscle and adipose tissue within 8 h. Heart lipoprotein lipase activity was significantly depressed only at doses of 0.1 mg endotoxin/kg body weight or greater. 3. Treatment of birds with 0.3 mg endotoxin/kg body weight reduced post-heparin lipoprotein lipase activity to 0.13 of that in control birds in 8 h. 4. Endotoxin generally depressed plasma very-low-density lipoprotein concentration. Plasma non-esterified fatty acid concentration was significantly elevated only in birds given 1 mg endotoxin/kg body weight. 5. Fatty acid synthetase activity in the liver of endotoxin-treated birds was significantly lower than in control birds 16 h after administration of endoxin, but not after 8 h. 6. These results show that tissue lipoprotein lipase activity in birds is very responsive to E. coli endotoxin, as in mammals. Hypertriglyceridaemia occurs only occasionally in endotoxin-treated chickens, most probably because of the particularly close relationship between food intake and hepatic lipoprotein synthesis in birds.     

Contribution of lipoprotein lipase activity to the differential growth of three adipose tissue depots in young broiler chickens

1. The growth of three distinct adipose tissue depots around the abdomen, neck and thigh was measured in a commercial strain of broiler, and related to the changes in activity of lipoprotein lipase within each depot.

2. At 10 d of age there was no significant difference between the weights of the depots. Thereafter the abdominal fat pad exhibited a much greater rate of growth than the other two depots so that by 55 d of age the abdominal fat pad was 4 times the size of the leg depot and 3.4 times the size of the neck depot.

3. Changes in total lipoprotein lipase activity for all three depots showed a similar pattern to the changes in their weight.

4. When [¹⁴C]‐VLDL was injected intravenously into birds at 15 and 57 d of age the percentage taken up into the abdominal fat pad was greater than that into the other two depots at both ages. At 57 d of age the abdominal fat pad had a 2.3‐fold greater uptake than at 15 d whereas the other two depots showed no significant differences at the two ages.

5. These results provide further evidence for a key role of lipoprotein lipase in regulating adipose tissue growth in broilers. They also demonstrate that although the abdominal fat pad has been used in a number of studies of adipose tissue metabolism it is not necessarily representative of other depots.     

矮小型肉鸡血浆极低密度脂蛋白浓度与腹脂性状的相关分析

以温氏育种公司黄鸡矮小型品系N30 1为材料 ,分析血浆VLDL浓度与腹脂性状间的关系 ,结果表明 :10周龄公母鸡血浆VLDL浓度的变异系数很大 ,分别为 4 9.86 %和 4 9.5 1% ;血浆VLDL浓度与脂肪性状间有较高程度的正表型相关 ,在公鸡中血浆VLDL浓度与皮脂重、皮脂率、腹脂重、腹脂率的表型相关系数分别为 0 .186 ,0 .117,0 .381和 0 .375 ,而在母鸡分别为 0 .2 2 8,0 .2 35 ,0 .2 5 8和 0 .2 5 2。血浆VLDL浓度可以作为矮小型鸡只体脂沉积性状的选种指标。     

Changes in lipoprotein metabolism and body composition in chickens in response to divergent selection for plasma very low density lipoprotein concentration

1. Plasma lipoprotein metabolism and body composition in lines of chicken selected for high- and low-plasma very low density lipoprotein (VLDL) concentrations were compared to the commercial broiler (meat-type) line from which they were derived. 2. Selection for low-plasma VLDL concentration for 10 generations has reduced the rate of VLDL secretion by at least 50% in males whereas selection for high-VLDL concentration has increased the rate of VLDL secretion over 2-fold. 3. Body fat content was highly correlated with rate of secretion of plasma triglyceride-rich (TGR) lipoproteins (r = 0.88 over the three lines). However, extrapolation of the data suggests that birds secreting no TGR-lipoproteins into the plasma would still have substantial amounts of body fat. 4. Selection for high VLDL has increased the proportion of circulating VLDL-triglyceride taken up by the abdominal fat pad by over 2-fold but there was no difference between high- and low-VLDL lines in the proportion of VLDL-triglyceride taken up by tissues and oxidised to [14C]-carbon dioxide. 5. The results confirm the importance of plasma lipoprotein metabolism in determining body composition in the chicken but suggest there are limits to further reduction in body fat content by manipulation of plasma lipoprotein metabolism.     

肉鸡血浆极低密度脂蛋白浓度与屠体肥度性状的相关研究

以白羽肉仔鸡为研究材料，４９日龄采血，用此法浊法测定血浆极低密度脂蛋白浓度。试验结果表明，血浆ＶＬＤＬ浓度的变异系数为５５％，其与腹脂重，腹脂率呈显著的正表型相关。体重和屠体重与腹膜重呈极显著的正表型相关，对血浆ＶＬＤＬ浓度的低向选择将间接低体重。为防止肉仔鸡上市体重的下降，应该同时考虑对血浆ＶＬＤＬ浓度和体重的选择。对血浆ＶＬＤＬ浓度的低向选择将降低腹膜重，腹脂率，肝脂含量和肝脂重而对胸肌脂肪含     

Lack of interrelationship between the effects of dietary factors and food withdrawal on carcase quality of broiler chickens

1. Four factorial experiments were carried out to determine whether there is any interrelationship between dietary energy-to-protein (E:P) ratio (experiments 1, 2 and 3) or pelleting the diet (experiment 4) and the duration of food withdrawal (FW), in their effect on carcase quality of broiler male chickens. The quality was evaluated by yields of carcase and breast meat, abdominal fat pad size, and the content and composition of the fat in the meat. The effect of sex on the response to FW was also determined in experiment 3 and that of age in experiment 4. 2. The diet with an E:P ratio higher than recommended decreased the weights of carcase and breast meat significantly (P 0.05) in 2 of the 3 experiments, and consistently increased the size of the abdominal fat pad and the fat content in thigh, but not in breast meat. Abdominal fat pad and the fat in meat of birds fed on this diet contained a significantly higher amount of oleic acid and a lower amount of linoleic acid, than the fat of birds fed on the diets with the recommended and the low E:P ratios. The pellets increased significantly the weights of carcase and breast meat and the relative size of abdominal fat pad. 3. FW for 24 h decreased significantly the weight at slaughter in all 4 experiments, carcase weight in 3 experiments, and breast weight in 1 experiment. However, it did not affect the relative size of the abdominal fat pad, the fat content in thigh and breast meat, and the composition of fatty acids in these tissues and in abdominal fat. None of the variables mentioned was affected significantly by the interaction between the dietary factors evaluated, sex or age of the birds on the one hand, and FW on the other hand. 4. It is concluded that the effect of 24 h of FW on weight at slaughter, carcase and breast meat weights and on fattening, is not affected by dietary E:P ratio, pelleting the diet, or sex and age of the broilers.     

The possible prediction of fatness in broiler chickens by biochemical measurements on adipose tissue

1. The possible prediction of fatness in 6-week-old broiler chickens was examined by measuring lipoprotein lipase (LPL) activity and lipid content in the abdominal adipose tissue. 2. Fat pad weight, as representing the degree of fatness in broiler chickens, was moderately well correlated (r = 0.54) with lipid content (g/100 g pad) and negatively correlated with LPL activity (r = 0.13). 3. It was concluded that the measurement of lipid content in samples from adipose tissue can be indicative of fatness of birds, while enzymic measurements are less valuable.     

Higher lipid accumulation in broilers fed on saturated fats than in those fed on unsaturated fats

1. Two experiments were conducted to assess the effect of fat sources differing in degree of saturation on the performance of and fat deposition in broiler chickens fed on isocaloric and isonitrogenous diets. 2. There were no differences in initial body weight between sexes but female broilers had lower daily gains (P <0.0001), final weights (P <0.0001) and food intakes (P <0.0001) than males. Abdominal fat pad weight was lower in male broilers than in female (P <0.001). 3. There were no significant differences in intake, weight gain, final body weight or food-to-gain ratios between birds fed on diets differing solely in the degree of fat saturation. Broilers fed on diets containing an animal fat blend or tallow had higher abdominal fat pad weight (P <0.001) and intramuscular lipid content (P =0.0085) than those fed on diets containing sunflower oil. 4. It was concluded that dietary fat saturation affects fat accumulation in broiler chickens.     

High dietary concentrations of biotin did not prevent foot pad dermatitis in growing turkeys and external scores were poor indicators of histopathological lesions

1. A randomised block experiment was conducted to determine the effects of increasing dietary biotin supplementation (0, 200, 800 and 1600 microg/kg) on macroscopic and histological changes associated with the development of foot pad dermatitis (FPD) in growing turkeys. 2. Each treatment was replicated in 4 pens containing 36 birds at the start of the experiment. The birds were weighed and external foot pads were scored at 2-week intervals from 2 to 14 weeks of age. A blood sample was obtained at the same ages from two birds in each pen and tissue from one foot pad was processed for histological examination. Liver samples were obtained for determination of fat content. 3. Increasing dietary biotin supplementation was associated with higher initial plasma concentrations of biotin but there was no effect on external scores or histopathology of foot pad lesions. FPD increased rapidly from 2 to 6 weeks and remained similar thereafter. There was no effect of dietary biotin on liver fat content. 4. The correlations between external foot pad scores at different ages were all less than 0.4. The correlation between external and histopathological scores was 0.56 and the respective correlations with body weight were 0.52 and 0.65. There were no differences between the body weights of birds with different external scores but high histopathological scores were associated with lower body weights. 5. It was concluded that current recommendations for biotin in wheat-soy rations for growing turkeys are adequate for normal growth and development and that higher supplements of biotin in these experimental conditions did not prevent the occurrence of FPD.     

Effect of dietary factors on the responses of chicks to corticosterone injections

Corticosterone-injected chicks fed on a diet based on sorghum gained less weight and accumulated more hepatic fat than chicks treated similarly and fed on a diet based on maize. The retention of nitrogen and dry matter and the apparent metabolisable energy of these diets were not affected by type of grain, either in corticosterone-injected or in untreated birds. A slight methionine deficiency in the maize diet resulted in an additional increase in the concentration of hepatic lipids in corticosterone-injected chicks. However, hepatic lipid concentration was not affected by either a deficiency or an excess of methionine in the diet based on sorghum. The dietary fat concentration of isocaloric and isonitrogenous diets and the energy concentration of diets containing similar energy-to-protein ratios did not affect the response of the chicks to corticosterone. There was a negative correlation between the relative weight gain of corticosterone-treated chicks and the relative hepatic fat content. The latter was positively correlated with relative abdominal fat pad size.     

The effect of increasing photoperiod and food restriction in sexed broiler-type birds. I. Growth and abdominal fat cellularity.

1. Sexed broiler-type chicks were raised either under a continuous (CON) 23 h Light (L) and 1 h Dark (D) schedule or an increasing photoperiod (INC) consisting of an initial 6 h L and 18 h D which increased by 4 h L per week from 14 to 35 d of age after which a 23 L:1D was maintained to 49 d of age. 2. From 5 to 11 d of age birds were fed either: ad libitum (AL), energy intake (kJ ME) restricted to 9.414 x gBW0.67 (R1) or energy intake (kJ ME) restricted to 6.276 x gBW0.67 (R2). Food intake was ad libitum at all other times. 3. Food restriction reduced growth to 49 d of age although some compensatory growth did occur. Food efficiency was not significantly affected by restriction. 4. Although abdominal fat pad weight was significantly reduced for R2 compared to AL, this was not significant on a percentage body weight basis. 5. Adipocyte number in the abdominal fat pad was similar for AL, R1 and R2, but concomitant with a smaller fat pad weight, R2 showed reduced adipocyte volume compared to AL. 6. INC birds were lighter at 21 d of age, but body weights were equivalent to CON by 42 d of age. 7. Abdominal fat pad weight was some 10% larger at 49 d of age for INC birds. Adipocyte volume was unaffected, the increase in adipocyte being entirely caused by an increase in adipocyte number in INC birds.     

Effects of methionine and betaine supplementation on growth performance, carcase composition and metabolism of lipids in male broilers

1. This study was conducted to investigate the effects of methionine and betaine supplementation on growth performance, carcase composition and lipid metabolism in growing broilers. 2. A total of 450 commercial broilers, 22 d of age, were randomly allocated to three groups, each of which included three replicates (50 birds per replicate). The groups received the same methionine-deficient diet supplemented with 0 or 1 g/kg methionine, or 0.5 g/kg betaine, respectively. 3. Methionine and betaine supplementation significantly improved weight gain and feed conversion. Supplemental methionine and betaine also significantly increased breast muscle yield and decreased abdominal fat content. Meanwhile, addition of methionine and betaine significantly increased the contents of creatine and free carnitine in liver, the activity of hormone-sensitive lipase in abdominal fat and the concentration of free fatty acid in serum, whereas uric acid concentration in serum was significantly decreased. 4. The results of this study suggest that betaine can spare methionine in its function as an essential amino acid and is as effective as methionine in improving performance and carcase quality of growing broilers if the diet is moderately deficient in methionine. The decrease in abdominal fat may be due to the increased carnitine synthesis in liver and hormone-sensitive lipase activity in abdominal fat.     

Effect of manganese supplementation and source on carcass traits, meat quality, and lipid oxidation in broilers

An experiment was conducted using a total of 336 one-day-old, Arbor Acres commercial male broilers to investigate the effect of dietary Mn supplementation on carcass traits, meat quality, lipid oxidation, relative enzyme activities in abdominal fat and meat, and Mn-containing superoxide dismutase (MnSOD) mRNA level in meat. Broilers were randomly allotted by BW to 1 of 8 replicate cages (6 chicks per cage) for each of 7 treatments in a completely randomized design involving a 2 x 3 factorial + 1 arrangement of treatments. Dietary treatments included the corn-soybean meal-based diet (control) and the basal diet supplemented with 100 or 200 mg of Mn/kg as MnSO(4) x H(2)O, Mn AA A with a chelation strength of 26.3 formation quotient (8.34% Mn), or Mn AA B with a chelation strength of 45.3 formation quotient (6.48% Mn). Birds fed supplemental Mn had lower (P < 0.10) percentages of abdominal fat, lipoprotein lipase (LPL), and malate dehydrogenase activities and greater (P < 0.07) hormone-sensitive lipase activities in abdominal fat than birds fed a control diet. Birds fed supplemental Mn from Mn AA A or Mn AA B had lower (P < 0.05) LPL activities in abdominal fat than those fed supplemental MnSO(4) x H(2)O. Birds fed supplemental Mn had lower (P < 0.03) malondialdehyde content in leg muscle and greater (P < 0.02) MnSOD activities and MnSOD mRNA level in breast or leg muscle than those fed the control diet. Birds fed supplemental Mn from Mn AA A had a greater (P < 0.02) MnSOD mRNA level in leg muscle than those fed supplemental MnSO(4) x H(2)O. Results from this study indicated that organic Mn was more available than inorganic Mn for decreasing LPL activity in abdominal fat of broilers, and dietary Mn might reduce abdominal adipose deposition by decreasing LPL and malate dehydrogenase activities or increasing hormone-sensitive lipase activity in abdominal adipose tissue. The results also indicated that dietary Mn upregulated muscle MnSOD gene expression pretranslationally in association with increased MnSOD activity, which might explain the decrease of malondialdehyde content in leg muscle.     

共轭亚油酸对北京油鸡肉品质及血清leptin和脂蛋白脂酶的影响

选用1日龄北京油鸡公雏360只,随机分成5个处理,每个处理6个重复,每个重复12只鸡,饲喂玉米豆粕型饲料基础日粮,添加0、0.25%、0.5%、1%、2%共轭亚油酸(CLA),用以研究CLA对北京油鸡脂类代谢和肉质性状的长期影响,试验期18周。结果表明:饲粮CLA提高了饲料利用率(P<0.05),显著性地降低了北京油鸡腹脂率和血清中脂蛋白脂酶(LPL)、leptin,显著增加了肌内脂肪的含量(P<0.05),但对pH值和肉色无显著性影响(P>0.05)。     

蛋鸡血浆VLDL浓度二世代双向选择对体脂沉积的影响

以雅发褐壳蛋鸡为素材,在零世代和一世代双向选择的基础上,应用血浆极低密度脂蛋白(VLDL)浓度对体腹脂性状继续进行双向选择,比较了高低脂系间体组成的差异,并研究了中后期血浆VLDL浓度与上述性状的相关程度,进一步探讨了血浆VLDL浓度的选择效应。结果表明:二世代母鸡中后期高脂系体重较高(P<0.05),血浆VLDL浓度与体重呈极显著的表型相关(P<0.01)和中等程度的正遗传相关。62周龄高脂系的腹脂率显著高于低脂系(P<0.05),说明运用血浆VLDL浓度经过二个世代的双向选择,使产蛋鸡中后期体重降低,且对腹脂沉积产生了一定的影响。     

Effect of dietary concentrations of fat and energy on fat deposition in broilers divergently selected for high or low abdominal adipose tissue

1. Fat deposition in abdominal, mesenterial, sartorial and gizzard adipose tissues (AT), liver, breast muscle, skin and carcase was studied in male broilers, selected for high (HF) and low (LF) abdominal fat and fed on diets differing in energy density and total fat content. 2. There were no significant differences in body weight in the experimental groups. The relative weight (g/kg body weight) of the dissected adipose tissues was higher in HF than in LF birds. Fat concentration in the AT (sartorial excepted), skin and body was higher in the HF compared with the LF birds. The lines did not differ significantly in liver and breast muscle fat content. 3. Abdominal AT was affected by selection or dietary fat more than other AT and total body fat. 4. In the HF birds increasing energy density from 12.3 to 13.4 MJ/kg (dietary fat kept constant: 5.46 g/MJ) significantly increased the weight of the abdominal, mesenterial and sartorial AT. Increasing dietary fat (at both energy densities) decreased the weight of the AT, whereas increasing both energy and fat did not affect it. In the LF birds, similar but milder and insignificant trends were observed. It is suggested that this interaction has biological significance.     

蛋用型鸡血浆极低密度脂蛋白浓度,肥度,生产性能之间的相关研究

以褐壳蛋鸡祖代母本种鸡为研究材料，用比浊法测定血浆极低密度脂蛋白浓度。试验结果表明，母鸡８１周龄腹脂重，腹脂率，鲜肝脂肪含量的变异系数分别高达４７％，３９％，４７％。表明这些性状在鸡群中未做过选择。血浆ＶＬＤＬ浓度与腹脂重，腹脂度，肝重，肝脂含量均呈正表型相关趋势。     

In ovo treatment with an aromatase inhibitor masculinizes postnatal hormone levels,abdominal fat pad content,and GH pulsatility in broiler chickens

Vorozole, a selective aromatase inhibitor, was administered in ovo to test the specific embryonic role of estrogen in conferring the sex distinction in GH release and body phenotype in broilers. On Day 6 of incubation, eggs were injected with saline or with different concentrations of vorozole. Postnatal blood samples were analyzed for T₃, T₄, GH, estradiol (E₂), and testosterone (T). At the age of 4 wk, control and vorozole-treated birds were cannulated, and serial blood samples were withdrawn every 10 min for 5 hr, wherein GH pulsatility characteristics were determined using deconvolution analysis. The proportional abdominal fat pad weight was reduced significantly in the treated groups, especially in female birds. The vorozole treatment increased plasma T₃, E₂, T, and GH concentrations, and decreased T₄. The frequency of the GH pulses was lower and the interval between the bursts (min) was higher in the vorozole-treated group, as were the mass secreted per burst (ng/ml), the amplitude (ng/ml/min) and the production rate (ng/ml/5 hr). In conclusion, early in ovo treatment with a potent aromatase inhibitor is able to increase the mean serum T₃ and GH concentration and masculinize the GH pulse pattern, resulting in an economically favorable decrease in abdominal fat pad content in male and female broilers at slaughter age.     

Single injection of clenbuterol into newly hatched chicks decreases abdominal fat pad weight in growing broiler chickens

The aim of the current study was to examine the effects of clenbuterol injection into newly hatched chicks on both the abdominal fat pad tissue weight and the skeletal muscle weight during subsequent growth. Twenty‐seven 1‐day‐old chicks were divided into two groups, receiving either a single intraperitoneal (i.p.) injection of clenbuterol (0.1 mg/kg body weight) or phosphate‐buffered saline (PBS). Body weight gain, feed intake and feed conversion ratio were not affected by clenbuterol injection during the 5‐week experimental period, while the abdominal fat pad tissue weight of the clenbuterol‐injected chicks was lower than that of the control chicks at 5 weeks post‐injection. Plasma non‐esterified fatty acid concentrations were significantly increased in the clenbuterol‐injected chicks, while plasma triacylglycerol concentrations did not differ. Additionally, the enzymatic activity of fatty acid synthase was lower in the liver of the clenbuterol‐injected chicks. Conversely, the skeletal muscle weights were not affected by clenbuterol injection. These results suggest that a single clenbuterol injection into 1‐day‐old chicks decreases the abdominal fat pad tissue weight, but may not affect skeletal muscle weights during growth. © 2015 Japanese Society of Animal Science