Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Backfat thickness”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed1997

Effectiveness of a pair-gain feeding strategy for individually fed, group-housed finishing pigs.

Crossbred barrows (n = 48) and gilts (n = 12) were used to examine the effectiveness of a pair-gain feeding strategy for individually fed, group-housed barrows. In a pair-gain feeding strategy, barrows were individually restricted to a feeding level at which their growth was similar to the mean growth of gilts with ad libitum access to feed. The purposes of this feeding strategy were to have barrows and gilts reach slaughter weight at the same time and to improve carcass traits of the barrows. At 29.8 +/- .4 kg BW, barrows were assigned to either the pair-gain or the ad libitum treatment. All pigs had free access to feed until they reached 60 kg BW. The experimental period was from 60 to 110 kg BW. The 12 group-fed gilts and 24 individually fed barrows (12 per pen) were also given free access to feed throughout the experimental period. The remaining 24 barrows (12 per pen) were put on a pair-gain feeding strategy. In the pair-gain feeding strategy, the weekly feed allowance of each barrow was based on its measured BW and computed energy conversion ratio and on the mean growth of the gilts. The barrows in the pair-gain treatment grew at the same rate as gilts. The ad libitum intake barrows grew faster (P < .05) and had a poorer energy conversion ratio for production than the barrows in the pair-gain treatment. The total energy conversion ratio, backfat thickness, and lean meat percentage were similar (P > .10) for the two treatments. In conclusion, the pair-gain feeding strategy was effective in achieving similar growth between barrows and gilts. The total energy conversion ratio and carcass traits of the barrows, however, were not improved.

Animals↗
PubMed1997

An evaluation of ultrasound and nuclear magnetic resonance spectroscopy to measure in vivo intramuscular fat content of longissimus muscle of pigs.

Intramuscular fat content (IMF) of longissimus muscle of pigs growing from approximately 20 to 100 kg was measured in vivo using biopsies after complete or localized anaesthesia, ultrasound and 1H nuclear magnetic resonance (NMR) technology. Three lines of pigs, with 60 animals each, were available. Biopsies were taken from the same pigs at 20, 60, and 100 kg, and fat was extracted for gravimetric determination. At 20 kg, ultrasound images were collected, and in vivo 1H NMR spectroscopy was applied. A-mode ultrasound measurements were collected at 60 and 100 kg. The overall mean value of IMF was 1.60 +/- .56% at 20 kg, 1.53 +/- .50% at 60 kg, and 1.71 +/- .60% at 100 kg. Interactions between lines and body weight were observed. No statistically significant differences were found between methods at 20 kg. No significant correlations were found between the A-mode ultrasound measurements and the mean values of the gravimetric measurements. No visible pain or infections were observed in relation to the collection of a single biopsy. The ultrasound method in combination with image analysis is advantageous from the labor point of view and will also improve welfare of pigs in case of repeated sampling. However, further research is necessary to make the technology sufficiently reliable. A correlation between IMF and backfat thickness was not found.

Animals↗
PubMed1997

Supplemental chromium picolinate influences nitrogen balance, dry matter digestibility, and carcass traits in growing-finishing pigs.

Four trials were conducted to determine the influence of feeding 200 ppb Cr as chromium picolinate (CrPic) on DM digestibility, N balance, and carcass traits of growing-finishing pigs. A 15% CP corn-soybean meal diet was fed during the grower phase, and a 13% CP corn-soybean meal diet was fed during the finisher phase. In each of three trials, crossbred barrows (six littermate pairs) were used for two N balance periods (end of grower, 61.3 kg; end of finisher, 98.9 kg). After the second balance period, all the barrows were killed and carcass data were collected. Initial and final BW were 23.5 and 104.9 kg, respectively. Growth rate was similar for control and CrPic-fed pigs in all trials. The rate of N absorption was increased by feeding CrPic (P < .05), but N retention was increased only numerically (P = .14). Dry matter digestibility was also increased by feeding CrPic (P < .02). Dressing percentage and backfat thickness at the 10th and last rib did not differ between treatment groups. Longissimus muscle area was larger (P < .05) for pigs fed CrPic. In Trial 4, crossbred barrows (six littermate pairs; initial BW, 82.0 kg) were used in a switch-back design with an extra period. Digestibility of DM (P < .02) and absorption of N (P < .06) were improved with only a numerical increase (P = .22) in N retention. No carryover effect was observed. These findings show that pigs fed 200 ppb Cr from CrPic can have larger longissimus muscle areas and that Cr supplementation improved N absorption and DM digestibility.

Absorption↗
PubMed1997

The effect of reducing excess dietary amino acids on growing-finishing pig performance: an elevation of the ideal protein concept.

Seventy-two gilts were used to determine the effect of reducing excess amino acid intake on growing-finishing pig performance. Separate diets were formulated for the growing (20 to 55 kg BW) and finishing (55 to 100 kg BW) periods. For each period, three diets were formulated that varied in total crude protein level and contained similar levels of digestible ideal protein. Crystalline amino acids were added to the low protein diets to overcome potential deficiencies. The grower diets contained .66% apparent ileal digestible lysine and contained 16.6, 15.0, and 13.0% CP, respectively; for the finisher diets, these values were .55% digestible lysine and 14.2, 12.8, and 11.0% CP, respectively. Amino acid analyses and a separate digestibility trial were conducted to confirm digestible amino acid levels in the dietary ingredients. During the growing and the overall growing-finishing period, daily gain, feed intake, and gain:feed were not affected (P > .10) by dietary treatment. Daily gain tended to be lower (P = .06) and gain:feed was poorer (P < .05) for pigs fed the 11.0% CP diet during the finishing phase. Although backfat thickness tended to be greater (P = .07) for pigs fed the lower-CP diet, estimated carcass lean yield was not affected (P > .10) by dietary treatment. Results of this study show that dietary CP can be reduced to 13% in the growing and 12.8% in the finishing diets of pigs as long as crystalline amino acids are added to match the apparent ileal digestible amino acid ratios in an assumed ideal protein.

Amino Acids↗
PubMed1997

Transfer of an ovine metallothionein-ovine growth hormone fusion gene into swine.

An ovine metallothionein-1a (oMT1a)-ovine growth hormone (oGH) fusion gene was microinjected into 400 pig zygotes, the zygotes were transferred into recipient females, and 15 founder transgenic pigs were born. Of 12 transgenic pigs assayed, five expressed high levels of oGH (> 900 ng/mL plasma), one expressed low levels of oGH (10 to 30 ng/mL), and six did not express oGH. Dietary supplementation with 2,000 ppm of zinc for 6 d induced a 20-fold increase in plasma oGH in the transgenic pig with low expression but did not induce expression in the six transgenic pigs with no constitutive oGH expression. The average daily gain of five transgenic pigs with elevated oGH was similar to that of non-transgenic littermates during a 9-wk feeding trial (P = .52). The liver, kidney, adrenal, and thyroid weights were all significantly heavier for the oGH-expressing transgenic pigs than for non-transgenic littermates. Total carcass fat, longissimus muscle fat, subcutaneous backfat thickness, and loin eye area were lower and carcass protein and water content and beta R fiber area of longissimus muscle were higher in the transgenic pigs with elevated oGH than in their littermate controls (P < .05 for each). The data indicate that even though the oMT1a promoter was more inducible by zinc than was previously reported for the mouse MT promoter in swine, the former provided a higher level of oGH expression than the mouse MT promoter.

Animals↗
PubMed1998

Effects of repeated urea dilution measurement on feedlot performance and consistency of estimated body composition in steers of different breed types.

Steers (20 Bos indicus cross [BIX] and 20 Bos taurus cross [BTX]) were randomly assigned to a 2x2 factorial experiment within two weight blocks per treatment 1) to study the effects of repeated urea dilution (UD) measurement on feedlot performance and 2) to determine the consistency of estimated body composition in steers of different breed types. Weights were taken on d 0, 42, 84, 126, and 140. Urea dilution was determined on half of the pens in the experiment, and ultrasonic measurement of backfat (BF) was performed on all cattle on d 0, 42, 84, and 126. Pen means of all performance variables were used in the analysis of variance. Carcass data were analyzed on an individual basis. Within periods, ADG was inconsistent between controls and steers on which UD was determined (1.95 vs 2.03, 1.61 vs 1.28, 1.51 vs 1.71, and 1.77 vs 1.47 kg, P = .23, .02, .09, and .11, respectively, for Periods 1, 2, 3, and 4, SEM = .07). Overall, UD had no effect (control vs UD, respectively) on ADG (1.70 vs 1.68 kg, P = .77, SEM = .07), DMI (8.26 vs 8.03 kg, P = .69, SEM = .36), gain efficiency (207 vs 209 g BW gain/kg DMI, P = .78, SEM = 2.34), hot carcass weight (HCWT; 360 vs 358 kg, P = .90, SEM = 2.52), or percentage of estimated carcass fat, (ECF; 38.8 vs 37.0%, P = .61, SEM = 1.05). Breed types (BIX vs BTX, respectively) had similar ADG (1.74 vs 1.64 kg, P = .27, SEM = .14), DMI (7.96 vs 8.30 kg, P = .50, SEM = .36), backfat thickness (16.4 vs 15.0 mm, P = .30, SEM = .45), and ECF (38.9% vs 36.6%, P = .48, SEM = 2.01). Urea dilution estimated empty body fat values increased with days on feed (14.4+/-1.36; 22.7+/-1.47; 26.0+/-1.36; 30.4+/-1.47%, respectively, for d 0, 42, 84, and 126). Using yield grade factors to calculate ECF consistently produced a value that was higher than empty body fat determined by UD (UDEBF) 14 d prior to slaughter (36.9+/-1.73 vs 30.4%+/-0.17). Significant correlation coefficients were found for the pooled data between UDEBF vs BF, r = .84; UDEBF vs live weight, r = .99; UDEBF vs ECF, r = .82; and UDEBF vs percentage of carcass protein, r = -.99. This study demonstrated that there are no detrimental effects of the urea dilution procedure on performance characteristics of feedlot cattle. Beef cattle of different breed types may be accurately evaluated with urea dilution.

Adipose Tissue↗
PubMed1998

Survival, body weights, feed efficiency, and carcass traits of 7/8 White Composite and 1/8 Duroc, 1/8 Meishan, 1/8 Fengjing, or 1/8 Minzhu pigs.

Pigs were the progeny of White Composite boars mated to gilts that were either 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu and the remainder 3/4 White Composite. One-eighth Meishan and 1/8 Fengjing pigs averaged approximately .5 more nipples than 1/8 Duroc pigs and .2 more nipples than 1/8 Minzhu pigs (P < .05), respectively. Duroc, Meishan, and Minzhu crosses did not differ (P > .05) for survival at birth or at 14 and 28 d. Fengjing crosses had a lower survival rate (P < .05) at all three ages than Duroc and Meishan crosses. Duroc crosses were heavier (P < .05) than Chinese crosses at birth. At 56 d, Duroc and Meishan crosses did not differ (P > .05) for BW, but both were heavier (P < .05) than Minzhu crosses. Body weight at 70 d did not differ significantly (P > .05) among breed types. Duroc crosses were heavier (P < .05) than any of the Chinese crosses at 98, 126, and 154 d of age. At 154 d, Fengjing crosses were lighter (P < .05) than Meishan or Minzhu crosses. The effect of breed type was not detected for average probe backfat thickness of gilts at 99.7 kg. Duroc crosses consumed the most feed, and Fengjing crosses consumed the least during each interval and during the total period (P < .05). Feed consumption of Meishan and Minzhu crosses was intermediate to and significantly (P < .05) different from that of Duroc and Fengjing crosses. At 184 d of age, breed types did not differ (P > .16) for measures of carcass fat thickness, marbling score, color score, and firmness score. At 184 d of age, weights of all carcass cuts were heavier (P < .05) for Duroc than for Chinese crosses with the exception of untrimmed loin weight of Minzhu crosses. There were few significant differences among breed types when carcass traits were compared at a constant carcass weight, although Duroc crosses generally were superior. Relative to similar Duroc crosses, these results suggest that 1/8 Chinese pigs would grow less rapidly (P < .05) and produce less weight of trimmed lean cuts at a constant carcass weight.

Age Factors↗
PubMed1998

Reproduction of 3/4 White Composite and 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu gilts and sows.

Females were either 1/4 Duroc, 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu, and the remainder were 3/4 White Composite. A greater percentage of Fengjing crosses reached puberty than Duroc or Minzhu (P < .05), and Meishan crosses were intermediate and not different (P > .05) from other breed types. After adjusting for differences in percentage detected owing to termination of observation for estrus, breed types ranked Fengjing, Meishan, Minzhu, and Duroc from youngest to oldest at puberty with approximately 14 d between adjacent breed types. Meishan and Fengjing crosses had a greater (P < .05) ovulation rate than Minzhu or Duroc crosses. With the exception of number of fetuses at 100 d and average fetal weight at 60 d, differences among breed types were not detected (P > .05) for litter or uterine traits measured on gilts slaughtered at 60 or 100 d of gestation. Total number of pigs born was greater (P < .05) for 1/4 Fengjing than for 1/4 Duroc gilts. Gestation length, number born alive, number weaned, litter birth weight, or litter weaning weight for gilts did not differ (P > .05) among breed types. Duroc crosses were heavier (P < .01) than Chinese crosses at d 1 and 28 after farrowing, but breed types did not differ (P > .05) for backfat thickness at those times. Breed types did not differ (P > .05) for the ratio of litter gain from 0 to 28 d/total Mcal or any of the component traits in the ratio. Postweaning estrus activity, conception rate, and litter and uterine traits of sows bred for second parity were not affected (P > .05) by breed type. These analyses indicate that crossbred gilts containing 1/4 Meishan, 1/4 Fengjing, or 1/4 Minzhu will reach puberty earlier, have larger litters, and weigh less at first parity than gilts containing 1/4 Duroc, but they do not have any significant advantage in litter size at second parity.

Animals↗
PubMed1998

Biases associated with genotype and sex in prediction of fat-free lean mass and carcass value in hogs.

Carcass and live measurements of 165 market hogs that represented seven genotypes were used to investigate genotype and sex biases associated with the prediction of fat-free lean mass (FFLM) and carcass value. Carcass value was determined as the sum of the product of weight of individual cuts and their average unit prices adjusted for slaughter and processing costs. Independent variables used in the prediction equations included carcass measurements, such as optical probe, midline ruler, ribbed carcass measurements, and electromagnetic scanning (EMSCAN), and live animal ultrasonic scanning. The effect of including subpopulation mean values of independent variables in the prediction equations for FFLM and carcass value was also investigated. Genotype and sex biases were found in equations in which midline backfat, ribbed carcass, EMSCAN, and live ultrasonic scanning were used as single technology sets of measurements. The prediction equations generally undervalued genotypes with above-average carcass value. Biases were reduced when measurements of combined technologies and mean adjusted variables were used. The FFLM and carcass value of gilts were underestimated, and they were overestimated of barrows. Equations that combined OP and EMSCAN technologies were the most accurate and least biased for both FFLM and carcass value. Equations that included carcass weight and midline last-rib backfat thickness measurements were the least accurate and most biased. Genotype and sex biases must be considered when predicting FFLM and carcass value.

Adipose Tissue↗
PubMed1999

Effect of genetic variants of the heart fatty acid-binding protein gene on intramuscular fat and performance traits in pigs.

In order to find genetic markers to improve the meat quality of pigs by breeding we studied the relationship between variation in the heart fatty acid-binding protein (H-FABP) gene (FABP3) and intramuscular fat (IMF) content. To estimate the effect of H-FABP, pigs from two Duroc populations were selectively mated in such a way that at least two genotypes were present in each litter. In total, data from 983 pigs and pedigree information from three preceding generations were analyzed. Offspring were tested for IMF content as well as backfat thickness (BFT), BW, and drip loss of the meat (DRIP). All pigs were assigned to H-FABP RFLP genotype classes either by the assessed genotype (75%) or based on a probability score determined according to genotypic information of their relatives (25%). Contrasts were detected between homozygous H-FABP RFLP genotype classes for IMF content (.4%, P < .05), BFT (.6 mm, P < .01), and BW (2.4 kg, P < .10). No significant contrasts were detected for DRIP. Results for IMF content, BFT, and BW were confirmed when only genotyped animals were analyzed. Variation in BFT partially explained the effect on IMF content. Although other closely linked genes on porcine chromosome 6 might be responsible for the observed effect, interference of the halothane gene was excluded because all parental animals were noncarriers. In conclusion, H-FABP RFLP can be used as markers to select for increased IMF content and growth in breeding programs.

Adipose Tissue↗
PubMed1999

Effect of protein intake during gestation and lactation on the lactational performance of primiparous sows.

The effect of protein intake during gestation and lactation on the lactational performance of primiparous sows was evaluated using 35 Yorkshire x Landrace gilts, allocated to six dietary treatments in a 3 x 2 factorial arrangement. Treatments consisted of three protein levels during gestation, providing approximately 4, 8, and 16 g of lysine/d, and two protein levels (low [L] and high [HI), providing approximately 15 and 45 g of lysine/d, during lactation, respectively. Diets provided similar amounts of ME and all other nutrients. As dietary protein increased during gestation, sows gained more weight and tended to decrease their backfat thickness. There was no gestation x lactation treatment interaction for lactational performance of sows. Feed intake by sows during lactation was usually low but increased (P < .05) with increasing gestation and lactation protein intake and increased linearly (P < .001) as lactation progressed. This linear increase over time was greater (P < .05) in sows fed the H than in sows fed the L protein level. Increased protein intake during lactation reduced (P < .001) 21-d sow weight loss. Milk yield and pig weight gain increased as protein intake increased during gestation (P < .05) and lactation (P < .01). Milk yield did not increase as lactation progressed (P > .05). Pig weight gain increased (P < .05) from wk 1 to 2 of lactation and decreased thereafter. Simple linear regression analysis detected few important relationships between yield of milk components and metabolites or metabolic hormone concentrations. The R2 values for these relationships were < or = .30, except for some relationships between milk component yields and blood urea nitrogen (the range was between .17 and .55). Covariate adjustment for metabolite and metabolic hormone concentrations did not eliminate treatment effects in most cases. This suggests that effects of increased protein intake on milk yield are not fully mediated through metabolite and metabolic hormone concentrations.

Amino Acids↗
PubMed1999

Effect of trimethylamine oxide and betaine in swine diets on growth performance, carcass characteristics, nutrient digestibility, and sensory quality of pork.

Two growth experiments and one digestibility experiment were conducted to study the effect of trimethylamine oxide (TMAO) and betaine in swine diets. In Exp. 1, 36 limit-fed pigs averaging 19.1 kg in initial weight were used to study the effect of adding TMAO at 10 g/kg of feed or betaine at an equivalent level of methyl groups (10.5 g/kg feed) to a high-fat (11.3% ether extract) basal diet. Dietary addition of TMAO increased ADG by 61 g/d, reduced number of days to market by 8.3 d (P<.02), and tended (P<.09) to improve gain/feed (G/F) compared with the control diet. Betaine had no effect on growth performance of pigs. Adding TMAO or betaine to diets had no effect on percent carcass fat, percent carcass lean, or dressing percentage. Dietary supplementation of TMAO reduced (P<.05) plasma triacylglycerol level (TAG) compared with the control diet. There was no effect of dietary TMAO or betaine on sensory quality characteristics of pork. In Exp. 2, 48 ad libitum-fed pigs averaging 21.7 kg initial BW and 104.7 kg final BW were used to determine the effect of adding low and intermediate levels of TMAO (1, 2, or 5 g/kg) to diets. Adding 1 g of TMAO increased G/F (P<.01) compared with control pigs. When using orthogonal contrasts, adding 2 g of TMAO reduced (P<.05) P2 backfat thickness and tended to increase (P<.09) lean percentage compared with the control diet. Trimethylamine oxide gave a quadratic effect (P<.05) on plasma TAG levels. Adding 1 and 2 g of TMAO increased plasma TAG, but 5 g of TMAO decreased it compared with the control diet. In Exp. 3, 12 barrows of 42.3 kg average initial BW and 50.0 kg final BW were used to investigate the effect of supplementing diets with 1 g of TMAO and 1.27 g of betaine/kg of feed on apparent total tract nutrient digestibility. The addition of TMAO increased (P<0.03) apparent total tract digestibility of fat (HCl-EE). Betaine had no such effect. Adding TMAO to diets influenced growth performance and carcass quality in a dose-dependent manner.

Animal Feed↗
PubMed2000

The effect of the Halothane and Rendement Napole genes on carcass and meat quality characteristics of pigs.

The objective of this study was to determine the effects of the Halothane (N) and Rendement Napole (RN) genes on carcass and meat quality characteristics in pigs. Halothane and RN carrier (Nn/RN- rn+) Hampshire boars (n = 4) were mated to dams that were homozygous for the normal allele of both genes (NN/rn+ rn+) to produce progeny of four genotypes: 1, NN/rn+ rn+ (n = 31); 2, Nn/rn+ rn+ (n = 27); 3, NN/RN- rn+) (n = 30); and 4, Nn/RN- rn+ (n = 23). A DNA test was used to determine Halothane genotype, and longissimus glycolytic potential was used to predict the RN genotype. Pigs were reared under standard conditions to approximately 120 kg live weight and slaughtered at a commercial plant, and carcass characteristics and meat quality were evaluated. Halothane carriers (Nn/ _ _), in comparison to Halothane normal (NN/_ _) pigs, had shorter carcasses, lower longissimus ultimate pH, higher Minolta L* and b* values, and greater drip loss. Rendement Napole gene carriers (_ _/RN- rn+) had higher L* and b* values and drip and cooking loss and lower longissimus ultimate pH than homozygous recessive animals (_ _/rn+ rn+). There were Halothane x RN genotype interactions (P < 0.05) for subjective color, firmness, and marbling scores, and for shear force. Animals that were normal for both genes (NN/rn+ rn+) had the highest subjective scores for color (2.60, 1.88, 1.85, and 1.95, SE = 0.181, P < 0.05), firmness (2.53, 2.03, 2.10, and 1.89, SE = 0.182, P < 0 .05), and marbling (2.11, 1.44, 1.53, and 1.55, SE = 0.153, P < 0 .05) for genotypes 1, 2, 3, and 4, respectively, suggesting darker, firmer muscle with a higher level of marbling for this genotype. Shear force was highest for Nn/rn+ rn+ animals (3.83, 4.41, 3.79, and 3.70, respectively, SE = 0.172, P < 0.05). Gilts had less s.c. backfat thickness, greater longissimus muscle area, and lower subjective marbling scores than barrows. There was no effect (P > 0.05) of gender on other meat quality traits. This study illustrates the negative effects of the Halothane and RN genes on fresh pork quality and suggests that in combination the detrimental effects of the two genes are additive for ultimate pH, objective color, and water-holding capacity.

Alleles↗
PubMed2000

The effect of adipocyte and heart fatty acid-binding protein genes on intramuscular fat and backfat content in Meishan crossbred pigs.

Effects of genetic variation in porcine adipocyte and heart fatty acid-binding protein genes, A-FABP and H-FABP, respectively, on intramuscular fat (IMF) content and backfat thickness (BFT) were examined in F2 crossbreds of Meishan and Western pigs. The involvement of each FABP gene in IMF accretion was studied to confirm previous results for Duroc pigs. The F2 crossbred pigs were genotyped for various markers including microsatellite sequences situated within both FABP genes. Linkage analysis assigned the A-FABP and H-FABP genes to marker intervals S0001-S0217 (20 cM) on SSC4 and Sw316-S0003 (16.6 cM) on SSC6, respectively, refining previous chromosomal assignments. Next, the role of both chromosome regions/genes on genetic variation in IMF content and BFT was studied by 1) screening SSC4 and SSC6 for QTL affecting both traits by performing a line-cross analysis and 2) estimation of the effect of individual A-FABP and H-FABP alleles on both traits. In the first analysis, suggestive and chromosome-wise significant evidence for a QTL affecting IMF was detected on SSC6. The H-FABP gene is a candidate gene for this effect because it resides within the large region containing this putative QTL. The second analysis showed a considerable but nonsignificant effect of H-FABP microsatellite alleles on IMF content. Suggestive evidence for a QTL affecting BFT was found on SSC6, but H-FABP was excluded as a candidate gene. In conclusion, present and previous results support involvement of H-FABP gene polymorphisms in IMF accretion independently from BFT in pigs. Therefore, implementation of these polymorphisms in marker-assisted selection to control IMF content independently from BFT may be considered. In contrast to previous findings for Duroc pigs, no evidence was found for an effect of the A-FABP gene on IMF or BFT in this population.

Adipocytes↗
PubMed2000

Somatotropin and adipose tissue metabolism: substrate and temporal effects.

The purpose of these studies was to determine the time course for changes in feed intake, blood metabolites, and lipogenic activity in adipose tissue in response to the initiation of porcine somatotropin (pST) treatment and following withdrawal from treatment in barrows. An initial study was conducted to determine the impact of chronic pST treatment (4 wk of daily injection; 0 vs 4 mg/d) on adipose tissue lipid metabolism in barrows (initial weight 67 kg). Feed efficiency was improved 27%, backfat thickness was decreased 43%, and glucose and lactate oxidation and incorporation into lipid in adipose tissue was reduced 70 to 86% in pST-treated pigs. Palmitate esterification was decreased 44%, whereas palmitate oxidation was unaffected. In vitro metabolism of lactate, glucose, and palmitate in liver slices was not affected by pST treatment. The time-course for changes in intake and adipose tissue metabolism in response to 7 d of pST (0 vs 4 mg/d) treatment and 7 d of withdrawal was examined in subsequent studies in barrows (initial weight 75 kg). Feed intake during pST treatment was significantly (P < .05) less than in control pigs within 24 h of the initiation of treatment and remained low through 3 d after withdrawal. Adipose tissue biopsies were obtained on d 0, 1, 2, 4, and 7 of the treatment phase and on d 2, 4, and 7 after withdrawal from 7 d of treatment. Maximal inhibition of lipogenesis by pST treatment in adipose tissue in vitro was observed on d 4 (-68%) and d 7 (-69%). Similarly, fatty acid synthase activity declined during the treatment period, with the greatest change noted on d 7 (-26%). After withdrawal from treatment, lipogenesis gradually increased, returning to control values 7 d after withdrawal. Levels of IGF-I began to increase from d 1 to d 7 of treatment, continually decreased during withdrawal, and were normalized by the end of the withdrawal period. Plasma urea nitrogen concentrations decreased during treatment, increased during the withdrawal phase, and were normalized 4 d after the last pST treatment. Overall results indicate that most of the metabolic changes in response to pST occur within 1 wk of treatment and return to pretreatment values after 7 d of withdrawal from treatment.

Adipose Tissue↗
PubMed2000

Effects of weaning age and diet on growth and carcass characteristics in steers.

Two experiments were conducted to determine the effects of diet on growth of steers weaned at approximately 100 vs 205 d of age. In Exp. 1, a 2 x 2 x 2 factorial experiment was conducted using 78 Angus crossbred cow-calf pairs. The factors examined were age at weaning (early, at 103+/-3 d [EW] vs normal, at 203+/-3 d [NW]), feeding strategy (ad libitum vs postweaning programmed intake), and dietary CP concentration (100 vs 120% of NRC [1984] recommended levels). Early-weaned calves had a greater (P < .001) ADG than NW calves from 103 to 203 d and reached market weight at 385 d vs 418 d for NW calves (P < .001). Likewise, steers offered feed for ad libitum consumption reached market weight at 394 d, compared with 409 d for programmed-intake steers (P < .05). In Exp. 2, 64 Angus crossbred steers were either weaned at 93+/-3 d and fed one of four diets, weaned at 210+/-3 d without access to creep feed, or weaned at 210+/-3 d with access to creep feed for 60 d prior to weaning. Early-weaned calves were heavier (P < .01) than NW calves at 210 d if fed either 100 or 90% concentrate diets, and they had greater (P < .001) backfat thickness at 210 d but no difference (P > .10) in longissimus muscle area compared to EW calves fed a 60% concentrate diet. At slaughter, 80 to 100% of steers on all treatments graded low Choice or higher. Feeding high-concentrate diets to EW beef calves accelerated growth rate and fat deposition early in the feeding period and may be a way to provide young cattle for a high-quality beef market.

Age Factors↗
PubMed2000

Effects of modified tall oil versus a commercial source of conjugated linoleic acid and increasing levels of modified tall oil on growth performance and carcass characteristics of growing-finishing pigs.

Two experiments were conducted to evaluate the effects of conjugated linoleic acid (CLA)-enriched feed additives for swine. These additives included a source of CLA that was commercially available (CLA-60) and modified tall oil (MTO). Experiment 1 used 36 barrows (initially 37.6+/-2.8 kg) to compare the effects of CLA-60 and MTO on growth performance and carcass characteristics of finishing pigs. The corn-soybean meal diets contained .50% soybean oil (control), .50% CLA-60, or .50% MTO. Pigs fed CLA-60 had less (P = .03) ADG from 37.6 to 72.6 kg than the control pigs; otherwise, pigs fed either CLA-60 or MTO had growth performance similar (P > .15) to that of the control pigs. Pigs fed MTO grew faster (P = .03) and consumed more feed (P = .10) over the duration of the experiment (37.6 to 106.4 kg) than pigs fed CLA-60. Dietary treatment did not affect (P > .15) plasma triglycerides or carcass characteristics, but pigs fed either MTO or CLA-60 had greater saturation of fatty acids in the adipose tissue at the 10th rib than pigs fed the control diet. Experiment 2 used 80 barrows (initially 33.4+/-2.2 kg) to examine the effects of increasing levels of MTO on growth performance and carcass characteristics of finishing pigs. The corn-soybean meal diet contained 1% cornstarch, which was replaced with MTO to give dietary levels of .25, .50, or 1.00% MTO. Dietary treatment did not affect (P > .15) growth performance. Feeding increasing levels of MTO quadratically decreased (P = .02) average backfat thickness and longissimus muscle drip loss (P = .04) and quadratically increased longissimus muscle area (P = .07) and percentage lean (P = .03). Feeding MTO tended to increase belly firmness (P < .10) compared with pigs fed the control diet. These traits appeared to be optimized with .50% MTO. In summary, pigs fed MTO had greater ADG, ADFI, and ending BW than pigs fed CLA-60. Feeding MTO does not appear to affect growth performance but improves carcass lean content and may additionally improve some aspects of meat quality in growing-finishing pigs.

Adipose Tissue↗
PubMed2001

Candidate gene markers for litter size in different German pig lines.

Three diallelic RFLP markers at candidate gene loci for litter size, the estrogen receptor (ESR) gene, the prolactin receptor (PRLR) gene, and the retinol-binding protein 4 (RBP4) gene, were evaluated for their association with the number of piglets born alive in different German pig lines. Genotyping was performed on boars and sows belonging to three different genetic groups from a single farm. Information on 8,336 litter records from 2,159 sows (German Landrace, n = 1,672; Duroc, n = 214; and a synthetic line, n = 273) was used in the analyses with respect to litter size. Growth performance traits were only analyzed for the synthetic line. The ESR locus showed no polymorphism in the tested boars of the German Landrace and Duroc lines. In the synthetic line, the frequency for the A allele was 0.90 and no homozygous BB animal was detected. No significant associations of ESR alleles with number of piglets born alive, backfat thickness, or average daily gain were observed. A new PCR-RFLP was developed for testing the PRLR polymorphism. The frequencies of PRLR allele A were 0.40 in the German Landrace, 0.49 in the synthetic, and 0.82 in the Duroc line. In the Duroc line, a small additive effect of the allele B on litter size was observed. The allelic substitution effect was 0.71 piglets born alive across all parities (P = 0.05). No significant associations of the PRLR locus with litter and growth performance traits were detected. The frequencies of RBP4 allele A ranged from 0.62 in the synthetic line to 0.67 in the German Landrace to 0.85 in the Duroc line. For the genotyped sows of the synthetic line, there was no indication of a favorable effect of the A allele with respect to litter size. Results of this study demonstrate that allele effects differ between lines or populations. This may be due to possible different linkage phases between the marker alleles and the causal mutations in the different lines. The results may also be explained by many minor genes affecting litter size. A selection strategy should be designed for each line separately and should always consider possible pleiotropic effects.

Animals↗