scholarly journals Metabolic and histochemical characteristics of fat and muscle tissues in homozygous or heterozygous pigs for the body composition QTL located on chromosome 7

2007 ◽  
Vol 30 (3) ◽  
pp. 232-241 ◽  
Author(s):  
Julie Demars ◽  
Juliette Riquet ◽  
Marie-Pierre Sanchez ◽  
Yvon Billon ◽  
Jean-François Hocquette ◽  
...  

Quantitative trait loci (QTL) influencing many traits including backfat thickness and carcass composition have been detected on porcine chromosome 7 (SSC7) in an F2 cross between Large White (LW) and Meishan (MS) pigs. However, the genes and controlled pathways underlying the QTL effects on body phenotype remain unknown. This study aimed at investigating the tissue characteristics at metabolic and cellular levels in pigs that were either homozygous or heterozygous for a body composition SSC7 QTL. A backcross pig (BC3) was first progeny tested to confirm its heterozygoty for the SSC7 QTL; results on all offspring ( n = 80) confirmed the QTL effects on body fatness. This boar was then mated with three sows known to be heterozygous for this QTL. In the subset of pigs per genotype, we found that heterozygous LWQTL7/MSQTL7 pigs had smaller adipocytes in backfat, together with a lower basal rate of glucose incorporation into lipids and lower activities of selected lipogenic enzymes in backfat isolated cells, compared with homozygous LWQTL7/LWQTL7 pigs. A higher number of adipocytes was also estimated in backfat of LWQTL7/MSQTL7 animals compared with LWQTL7/LWQTL7 pigs. The SSC7 QTL did not influence oxidative and glycolytic metabolisms of longissimus and trapezius muscles, as estimated by the activities of specific energy metabolism enzymes, or the myofiber type properties. Altogether, this study provides new evidence for an altered adipocyte cellularity in backfat of pigs carrying at least one MS allele for the SSC7 QTL. Some candidate genes known for their functions on adipocyte growth and differentiation are suggested.

Author(s):  
A J Kempster ◽  
G L Cook ◽  
M Grantley-Smith

1The relationship between diet and health is now a major factor in the development of production and marketing strategies for the British meat industry, following Government recommendations that people should be encouraged to eat less fat. It has emphasised the need for accurate information on the body composition of national livestock populations and the fat content of the meat and meat products derived from them. This paper collates the information available for cattle, sheep and pigs, and provides base-line (1984) estimates of national lean and fat production. Changes that have taken place over the past ten years are also examined.2The basic framework for making estimates was the distribution of carcasses between fatness ranges in the national carcass classification schemes operated by the Meat and Livestock Commission (MLC). The distribution for cattle was obtained from a random 1 in 3 sample of beef carcasses classified (0.25 of all clean beef carcasses were classified).3A computer spread-sheet was constructed relating the midpoint means of the fatness ranges to carcass tissue proportions and chemical composition. Regressions for predicting carcass lean and fat content were calculated from accumulated data from surveys of commercial carcasses and breed evaluations for cattle (Kempster, 1986), for sheep (Kempster, Jones and Wolf, 1986a) and for pigs (Diestre and Kempster, 1985). Key regressions are given in Table 1. Carcass lean and fat are defined as in the standard MLC tissue separation procedure. Regressions for estimating carcass lipid content: were obtained using data from several studies. The principal study involved carcasses from breed comparison trials (MAFF/MLC, 1982). Details of the other data sets are given by Kempster, Cook and Grantley-Smith (1986b). Key relationships are given in Table 2.4Estimates of the composition of carcasses in different classification fatness ranges are given in Table 3. These are for 'clean' cattle, sheep and pigs, but estimates were also made for cull cows and cull ewes.5National estimates of carcass composition and the weights of lean and fat produced in 1975/77 and 1984 are given in Table 4. The carcass composition of beef was the same in 1974/76 and 1984 but the average carcass weight has increased by 20kg. The implication of this is that changes in breed and production system have created the potential for leaner carcasses but that the beef industry has preferred to exploit this potential by increasing carcass weights. An increase of 20kg is equivalent to about 15gAg separable fat in carcass on the basis of typical regressions within breed and system.The carcasses of clean sheep in 1984 were estimated to be slightly lighter and leaner than those in 1977. Information on marketing patterns suggests that there has been little change in production methods (as far as they affect composition) and that lambs are now being slaughtered early, possibly stimulated by the pattern of Guide Prices in the EEC Sheep Meat Regime.In marked contrast to cattle and sheep, the separable fat content of the average pig carcass has fallen from 274g/kg in 1975 to 228g/kg in 1985, with a small increase in carcass weight. It is estimated that the increase in the use of entire males has contributed 5g/kg to the overall change.6The estimates in the paper are considered to be the best available with current information but because of the limitations of the data may be subject to error. Possible sources of error are discussed by Kempster et al (1986b). The authors would be pleased to know of data relating physical and chemical composition that could be used to refine the estimates.


1970 ◽  
Vol 75 (1) ◽  
pp. 19-26 ◽  
Author(s):  
R. P. Andrews ◽  
E. R. Ørskov

SUMMARY1. In an experiment with ninety-nine lambs the effects on the body composition of male and female lambs were examined when five diets containing different concentrations of crude protein (in the range 10–20%) were given at three levels of feeding and lambs were slaughtered at two live weights (27·5 and 40 kg).2. With lambs slaughtered at 27·5 kg there were significant increases in the rate of both nitrogen and fat retention with increases in levels of feeding. There were also linear increases in the rate of protein deposition and decreases in fat deposition with increases in the concentration of crude protein. This effect was particularly marked at the high level of feeding.3. With lambs slaughtered at 40 kg live weight there were also linear increases in fat and in nitrogen deposition with increasing feeding level but the effect of increasing the protein concentration on increases in nitrogen retention departed from linearity.4. While at 27·5 kg there were no significant effects of feeding level on nitrogen and ether-extract content of the bodies at slaughter, with animals slaughtered at 40 kg there was a significant linear decrease in ether-extract content with increasing feeding level and a corresponding linear increase in nitrogen content with increased level of feeding.5. Male lambs deposited more nitrogen and less fat than females. This was true of both rate of deposition and of carcass composition at 40 kg live weight.


1964 ◽  
Vol 6 (3) ◽  
pp. 309-319 ◽  
Author(s):  
S. K. Stephenson

1. Body shape and carcass composition have been measured in a dated series of Romney-Southdown cross and Australian Merino sheep foetuses.2. Large differences in shape exist between the two breed groups and these result from growth rate differences in certain components of the bone and muscle tissue.3. Carcass composition at any particular foetal weight, however, is more uniform. In relation to body weight, the Merino has a higher proportion of bone in the body but the proportion of muscle is the same in both breed groups. Nevertheless, the distribution of muscle tissue is changed as there s i a higher proportion of muscle in the hind limb of the Romney-Southdown cross.


1987 ◽  
Vol 44 (3) ◽  
pp. 371-385 ◽  
Author(s):  
J. France ◽  
M. Gill ◽  
J. H. M. Thornley ◽  
P. England

ABSTRACTA simple dynamic model of metabolism in growing beef cattle is described; the scheme is based on carbon and nitrogen fluxes. There are six state variables, three relating to blood metabolite levels and three to body composition. The blood metabolite variables are acetyl-coenzyme A equivalents, glucose equivalents and amino acids, and the body composition ones are ash, lipid and protein. The fluxes in the model are based on nine biochemical transactions, six of which are catabolic and three biosynthetic. The model simulates changes in carcass composition in response to changing nutrient input and gives a measure of agreement with comparative slaughter data. It also highlights the need for more complete data on profiles of nutrient absorption in association with comparative slaughter experiments.


1995 ◽  
Vol 75 (4) ◽  
pp. 517-524 ◽  
Author(s):  
K. L. Hammell ◽  
J. P. Laforest ◽  
J. J. Dufour

Data from approximately 850 commercial pigs tested in 12 trials, from 1987 to 1990 at the Beaumont test station in Québec were used to determine the effect of growth rate and body composition on growth performance, carcass yield and lean meat colour. Pigs were housed four to a pen and were fed commercial diets. Feed intake and growth rate were measured during the test, and carcass measurements were taken at slaughter and at 24 or 72 h following slaughter. The different groups of pigs were defined according to a 2 × 2 factorial, with one factor being the growth rate [fast growth (FG) or slow growth (SG)] and the second factor being the body composition of the carcass [fat (F) or lean (L)]. The FG commercial pigs reach market weight at a younger age with lower overall feed consumption and generally a better feed conversion than SG pigs. Furthermore, FG pigs have more backfat, longer carcasses and a slightly darker meat. The L commercial pigs had similar growth performances with a better lean meat yield than the F commercial pigs. Growth variables and composition of the carcass had little effect on the meat characteristics measured. The proportion of barrows compared to gilts was higher in the FG and F groups than in the SG and L groups, which could account for some of the differences observed between groups. However, the rate of growth and the type of body composition affected the growth and feed consumption performances as well as the carcass yield in a similar way for both sexes. Overall, less than 3% and less than 2% of the pigs produced meat with a colour standard of 1 (extremely pale) or 5 (extremely dark), respectively. The SG-L group had a slightly higher proportion of pigs with a pale meat colour compared to the other groups. Key words: Pig, backfat, growth rate, carcass composition, meat colour


1984 ◽  
Vol 39 (2) ◽  
pp. 177-193 ◽  
Author(s):  
R. M. Seebeck

ABSTRACTComparative slaughter was used to assess the body composition of Shorthorn-Hereford (SH), Africander cross (A×), Brahman cross (B×), and late castrated Brahman cross (B×(late)) steers of the F, generation with respect to their yield of carcass, gross carcass composition and offal composition. Animals were slaughtered at pre-determined weights of 315, 355, 399, 449 and 505 kg.The B× animals had the highest carcass yield (expressed either as dressed carcass weight at the same fasted body weight or at the same empty body weight), while the A×, B×(late) and SH animals had similar carcass yield. Within a breed, rate of growth affected carcass yield, with faster growing animals having the lower carcass yield, particularly with respect to fasted body weight.The breeds were different in carcass composition but this was dependent on both size and growth rate. Brahman cross animals had a lower proportion of bone than A× and SH animals, particularly at the higher body weights. Faster growing animals tended to contain more muscle and bone and less fat, with the exception of the SH animals.The breeds were also significantly different in the composition of the offal components. A× were notable for high head weights and low tail weights, B× having high blood weights and low total gut tissue weights, and Bx(late) having high hide weights and low abdominal fat weights.Rate of growth had some effect on offal composition, the general trend being that the faster growing animals were characterized by a lower proportion of heart, blood and pancreas. However there was also evidence that the rate of growth differentially affected the offal composition with respect to breeds. This effect mainly arose because the faster growing B×(late) animals had lower weights of abdominal fat. Within the other breeds, the opposite trend was observed.


1984 ◽  
Vol 247 (1) ◽  
pp. R183-R188 ◽  
Author(s):  
T. R. Vilberg ◽  
R. E. Keesey

Activity, O2 consumption, and body composition were measured in female rats with lesions of the ventromedial hypothalamus (VMH). One group of lesioned rats was food restricted to maintain body weights at control levels. O2 consumption of these food-restricted VMH-lesioned rats was 13% lower than that of nonlesioned rats. About half this energy savings accrued from reduced activity; the remainder resulted from a decline in resting metabolic rate (RMR). Though matched in weight to controls, the body composition of the restricted VMH-lesioned rats was abnormal. Their carcass protein was reduced by 12%, whereas fat was elevated 200%. The replacement of lean metabolically active tissue by carcass fat appears to underlie the reduction in RMR, an interpretation supported by multiple-regression analysis of carcass composition. Ad libitum-fed VMH-lesioned rats did not show this carcass protein decline, though their fat was elevated 895%. These results confirm that reduced activity contributes to energy savings and weight gain after VMH lesions. Likewise, restricting weight of VMH-lesioned rats to control levels reduced RMR, apparently because carcass protein declines. But, since ad libitum-fed female VMH-lesioned rats do not display reduced carcass protein, the historic assumption that RMR reductions contribute to their obesity appears unwarranted.


Author(s):  
S. O'Dowd ◽  
S. Hoste ◽  
J.T. Mercer ◽  
V.R. Fowler ◽  
S.A. Edwards

Selection for the reduction of carcase fat and the promotion of lean tissue growth has resulted in the production of faster growing, genetically lean breeding females. These animals often have very limited body fat reserves to utilise at times of high nutrient demand, such as during lactation. It is possible that reproductive performance and longevity may be improved as a consequence of alteration of the body composition of the breeding female by nutritional means.The experiment was designed to investigate the consequences for genetically lean animals of restricting lean tissue growth and promoting fat deposition in the period prior to a maiden service and in gestation using a low protein diet, and minimising fat loss in lactation using a nutrient dense diet (Treatment E) in comparison with feeding a conventional single diet (Treatment C). Two hundred and forty purebred Large White and Landrace gilts were allocated to one of these two nutritional regimes at 6 months of age on the basis of breed, liveweight and backfat. Animals remained on treatment for three parities and growth and performance parameters were monitored.


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