• Animal Bioscience
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• v.36 no.9
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• pp.1314-1326
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• 2023

Sheep and goats can efficiently convert low quality forage into high-quality meat which contains specific nutrients and quality traits. Carcass traits and quality attributes of sheep and goat meat depend upon several factors and one of most effective strategies amongst these is feeding regimens. In this review, the major aspects of feeding regimens affecting growth rate, carcass traits and quality attributes of sheep and goat meat are thoroughly discussed, with a particular focus on physical-chemical composition, flavor profile, and fatty acid (FA) profile. Grazing lambs and kids receiving concentrate or under stall-feeding systems had greater average daily gain and carcass yield compared with animals reared on pasture only. However, growth rate was higher in lambs/kids grazing on pastures of improved quality. Moreover, the meat of grazing lambs receiving concentrate had more intense flavor, intramuscular fat (IMF) content, and unhealthy FA composition, but comparable color, tenderness, juiciness, and protein content compared to that of lambs grazed on grass only. In contrast, meat of concentrate-fed lambs had more intense color, greater tenderness and juiciness, IMF and protein contents, and lower flavor linked to meat. Additionally, the meat of kids grazed on concentrate supplementation had higher color coordinates, tenderness, IMF content and unhealthy FA composition, whereas juiciness and flavor protein content were similar. In contrast, kids with concentrate supplementation had superior color coordinates, juiciness, IMF content and unhealthy FA composition, but lower tenderness and flavor intensity compared to pasture-grazed kids. Thus, indoor-finished or supplemented grazing sheep/goats had higher growth rate and carcass quality, higher IMF content and unhealthy FA composition compared to animals grazed on grass only. Finally, supplementation with concentrate increased flavor intensity in lamb meat, and improved color and tenderness in kid meat, whereas indoor-fed sheep/goats had improved color and juiciness as well as reduced flavor compared to pasture-grazed animals.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.10
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• pp.1464-1469
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• 2006

The present study was conducted with twenty-four Korean native (Hanwoo) steers to observe the effect of mixed oil and monensin supplementation and duration of feeding on c9,t11-CLA content in plasma and fat tissues. The steers were randomly assigned to three groups of eight animals each according to body weight. Hanwoo steers in the control group were fed the commercial concentrate for the late fattening stage. The other groups of steers were fed the same diet as control steers, but the concentrate was supplemented with high-$C_{18:2}$ oil mixture (soybean oil, sunflower oil, safflower oil) and fish oil at 6% level of concentrate (DM basis), and monensin (20 ppm). The second and third group of steers was fed the oil mixture supplemented diet with monensin for the last 10 weeks and 20 weeks, respectively, prior to being slaughtered. The oil mixture consisted of 45% soybean oil, 20% sunflower oil, 20% safflower oil and 15% fish oil. Average daily gain (p<0.049) and feed efficiency (p<0.018) of the steers fed the diet supplemented with oil mixture and monensin (OM-M) for 20 weeks were higher than those of the other groups of steers. Dressing percent, fat thickness and longissimus muscle area were not affected by the OM-M supplementation and duration of its feeding. The OM-M supplementation increased the content of total-cholesterol (p<0.0001-0.0007) and HDL-cholesterol (p<0.0001) in the plasma of steers compared to the control diet. The steers fed the OM-M diet had a higher proportion of c9,t11-CLA in plasma (p<0.048-0.044) than the control steers. Feeding the OM-M diet for 20 weeks increased the proportion of CLA in intramuscular (p<0.015), intermuscular (p<0.039) and subcutaneous (p<0.001) fat tissues compared with both steers fed the control diet and the OM-M diet for 10 weeks. Increased (p<0.007) proportion of total unsaturated fatty acids in steers fed the OM-M diet for 20 weeks compared to those in control steers was related to the increased (p<0.001) $C_{18:2}$ and decreased (p<0.001) $C_{18:0}$ proportions in subcutaneous tissue.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.9
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• pp.1225-1233
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• 2009

Fat composition of beef, taken here to mean marbling, can be manipulated by time on feed, finishing diet, and breed type. These three factors also strongly influence the fatty acid composition of beef. Both the amount of marbling and the concentration of monounsaturated fatty acids (MUFA) increase with time on feed in grain-fed and pasture-fed cattle, but much more dramatically in grain-fed cattle. High-concentrate diets stimulate the activity of adipose tissue stearoyl-CoA desaturase (SCD), which is responsible for the conversion of saturated fatty acids (SFA) to their $\Delta{9}$ desaturated counterparts. Also, grain feeding causes a depression in ruminal pH, which decreases those populations of ruminal microorganisms responsible for the isomerization and hydrogenation of polyunsaturated fatty acids (PUFA). The net result of elevated SCD activity in marbling adipose tissue and depressed ruminal isomerization/hydrogenation of dietary PUFA is a large increase in MUFA in beef over time. Conversely, pasture depresses both the accumulation of marbling and SCD activity, so that even though pasture feeding increases the relative concentration of PUFA in beef, it also increases SFA at the expense of MUFA. Wagyu and Hanwoo cattle accumulate large amounts of marbling and MUFA, and Wagyu cattle appear to be less sensitive to the effects of pastures in depressing overall rates of adipogenesis and the synthesis of MUFA in adipose tissues. There are small differences in fatty acid composition of beef from Bos indicus and Bos taurus cattle, but diet and time on feed are much more important determinants of beef fat content and fatty acid composition than breed type.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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• pp.127-134
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• 2015

Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cattle, resulting in improved beef quality. However, little is known about the metabolic adaptations in the liver following castration. To understand changes in lipid metabolism following castration, hepatic expression levels of lipid metabolism genes were compared between Korean bulls and steers. Steers had higher (p<0.001) hepatic lipids contents and higher (p<0.01) mRNA levels of lipogenic acetyl-CoA carboxylase. This differential gene expression may, in part, contribute to increased hepatic lipid content following the castration of bulls. However, we found no differences in the hepatic expression levels of genes related to triglyceride synthesis (mitochondrial glycerol-3-phosphate acyltransferase, diacylglycerol O-acyltransferase 1 and 2) and fatty acid (FA) oxidation (carnitine palmitoyltransferase 1A, C-4 to C-12 straight chain acyl-CoA dehydrogenase, very long chain acyl-CoA dehydrogenase) between bulls and steers. No differences in gene expression for very-low-density lipoprotein (VLDL) secretion, including apolipoprotein B mRNA and microsomal triglyceride transfer protein (MTTP) protein, were observed in the liver although MTTP mRNA levels were higher in steers compared to bulls. In conclusion, FA synthesis may contribute to increased hepatic lipid deposition in steers following castration. However, hepatic lipid metabolism, including triglyceride synthesis, FA oxidation, and VLDL secretion, was not significantly altered by castration. Our results suggest that hepatic lipid metabolism does not significantly contribute to increased body fat deposition in steers following castration.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.590-600
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• 2005

The present report has been aimed at reviewing important factors which need to be closely analyzed or considered when increasing the market weight of finishing pigs. The pig market weight has increased worldwide during the past few decades, which is attributable primarily to an increased lean gain potential of finishing pigs. To increase the market weight, however, the acceptability of larger pigs by the packer as well as pork consumers should be met first. By increasing the market weight, total number of breeding stock, as well as the facility for them, necessary for producing a given weight of pork can be reduced, whereas more building space for finishing pigs and an additional nutrition program for the later finishing period are needed. Additionally, a more thorough disease prevention program especially against ileitis and mycoplasma pneumonia may also be needed, because outbreaks of these are known to increase with increasing body weight over 110 kg. Some larger finishing pigs may deposit excessive fat that may be reduced or prevented by using hormonal and/or nutritional agents. Backfat thickness increases linearly with increasing body weight between 110 and 130 kg, whereas intramuscular fat content does not change significantly. With increasing live weight within this range, the ratios of belly and loin to carcass weight also are known to increase. Some physicochemical characteristics related to fresh and cooked meat quality including color, firmness, juiciness, etc. are known to be unaffected or slightly changed following an increase of slaughter weight. In conclusion, ratios of primal cuts and pork quality characteristics are not significantly affected by increasing the market weight. Moreover, increasing the market weight of lean-type pigs approximately up to 130 kg is normally profitable to producers, as long as packers and consumers accept larger pigs.

• Animal Bioscience
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• v.35 no.2
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• pp.155-165
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• 2022

Objective: This study was performed to examine whether the porcine glutamic-oxaloacetic transaminase 1 (GOT1) gene has important functions in regulating adipocyte differentiation. Methods: Porcine GOT1 knockout and overexpression vectors were constructed and transfected into the mouse adipogenic 3T3-L1 cells. Lipid droplets levels were measured after 8 days of differentiation. The mechanisms through which GOT1 participated in lipid deposition were examined by measuring the expression of malate dehydrogenase 1 (MDH1) and malic enzyme (ME1) and the cellular nicotinamide adenine dinucleotide phosphate (NADPH) content. Results: GOT1 knockout significantly decreased lipid deposition in the 3T3-L1 cells (p<0.01), whereas GOT1 overexpression significantly increased lipid accumulation (p<0.01). At the same time, GOT1 knockout significantly decreased the NADPH content and the expression of MDH1 and ME1 in the 3T3-L1 cells. Overexpression of GOT1 significantly increased the NADPH content and the expression of MDH1 and ME1, suggesting that GOT1 regulated adipocyte differentiation by altering the NADPH content. Conclusion: The results preliminarily revealed the effector mechanisms of GOT1 in regulating adipose differentiation. Thus, a theoretical basis is provided for improving the quality of pork and studies on diseases associated with lipid metabolism.

• Journal of Animal Science and Technology
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• v.62 no.5
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• pp.753-760
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• 2020

The objective of this study was to investigate the influence of increasing carcass weight (CW) on meat quality traits including meat color, water-holding capacity (WHC), tenderness, backfat thickness and intramuscular fat (IMF) content of pork loin. A total of 96 pork carcasses (48 LYD [Landrace × Yorkshire × Duroc] barrows and gilts) were selected at a commercial slaughterhouse. Each gender had commercial CW (≤ 90 kg), heavy CW (91-100 kg) and very heavy CW (> 100 kg) (16 carcasses from each CW group). Loin cuts (Longissimus lumborum) were excised to investigate meat color (CIE L*a*b*), drip loss, cooking loss, released water, Warner-Bratzler shear force (WBSF), and IMF content. Backfat thickness and IMF content of pork loin samples were significantly (p < 0.05) increased with increasing CW, although there was no significant difference in ultimate pH (pHu). CIE a* increased significantly (p < 0.05) with increasing CW, while there were no significant differences in CIE L* or CIE b* among CW groups. Although all WHC measures showed no significant differences among CW groups, WBSF increased significantly (p < 0.01) with increasing CW. Sensory flavor score was significantly increased while panel score for tenderness was decreased significantly (p < 0.001) with increasing CW. Consequently, CW had a positive correlation with flavor but negative correlation with tenderness. These results indicate that the increased IMF content improves flavor, juiciness and palatability, although tenderness deteriorates with increasing CW.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.9
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• pp.1229-1238
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• 2016

This study was conducted to determine the relationships of five intragenic single nucleotide polymorphism (SNP) markers (protein kinase adenosine monophosphate-activated ${\gamma}3$ subunit [PRKAG3], fatty acid synthase [FASN], calpastatin [CAST], high mobility group AT-hook 1 [HMGA1], and melanocortin-4 receptor [MC4R]) and meat quality traits of Duroc breeding stocks in Korea. A total of 200 purebred Duroc gilts from 8 sires and 40 dams at 4 pig breeding farms from 2010 to 2011 reaching market weight (110 kg) were slaughtered and their carcasses were chilled overnight. Longissimus dorsi muscles were removed from the carcass after 24 h of slaughter and used to determine pork properties including carcass weight, backfat thickness, moisture, intramuscular fat, $pH_{24h}$, shear force, redness, texture, and fatty acid composition. The PRKAG3, FASN, CAST, and MC4R gene SNPs were significantly associated with the meat quality traits (p<0.003). The meats of PRKAG3 (A 0.024/G 0.976) AA genotype had higher pH, redness and texture than those from PRKAG3 GG genotype. Meats of FASN (C 0.301/A 0.699) AA genotype had higher backfat thickness, texture, stearic acid, oleic acid and polyunsaturated fatty acid than FASN CC genotype. While the carcasses of CAST (A 0.373/G 0.627) AA genotype had thicker backfat, and lower shear force, palmitoleic acid and oleic acid content, they had higher stearic acid content than those from the CAST GG genotype. The MC4R (G 0.208/A 0.792) AA genotype were involved in increasing backfat thickness, carcass weight, moisture and saturated fatty acid content, and decreasing unsaturated fatty acid content in Duroc meat. These results indicated that the five SNP markers tested can be a help to select Duroc breed to improve carcass and meat quality properties in crossbred pigs.

• Nutritional Sciences
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• v.8 no.3
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• pp.181-188
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• 2005

We investigated the effects of diet manipulation on pro- and macro-glycogen accumulation and mobilization during exercise in different kinds of muscle fiber and tissue. Thirty-two Sprague-Dawley rats were divided into groups representing one of two dietary conditions: high fat (HF, n=16) or standard chow (CHOW, n=16). Each dietary group was fm1her divided into control (REST, n=8) and exercise (EXE, n=8). After an eight-week dietary intervention period, the animals in EXE swam for 3 hours while the animals in REST remained at rest Skeletal muscle (soleus, red gastrocnemius and white gastrocnemius) and liver samples were then dissected out and used for analyses. 1here was no statistical difference in body weight between the animals in the HF and mow groups (p>.05). Three hours of exercise significantly increased plasma free fatty acid (FFA) concentration in the animals in the CHOW group but not in the animals in the HF group. Both citrate. synthase (CS) and $\beta$-hydroxyacyl dehydrogenase ($\beta$-HAD) activities in skeletal muscles were higher in the HF group than in the mow group. CS and $\beta$-HAD activities were also the highest in red gastrocnemius and the lowest in white gastrocnemius. At both time points (i.e., rest and immediately after exercise) intramuscular triglyceride (IMTG) and liver TG concentrations were significantly higher in the HF compared to the CHOW. IMTG and liver TG changed selectively in the CHOW. Except in white gastrocnemius muscle, there was no significant difference in total glycogen content between HF and mow at rest. Although exercise significantly lowered total glycogen content in all groups and tissues (p<.05), the degree of reduction was markedly greater in the mow than in the HF. Whereas changes in proglycogen concentration showed a trend similar to those of total glycogen, alterations in macroglycogen concentrations clearly differed from those of total glycogen. Specifically, the degree of reduction of macroglycogen following three hours of exercise was substantially greater in the CHOW than in the HF. These results suggest that metabolic alterations induced by a long-term high fat diet may be caused by macro-glycogen rather than pro-glycogen.

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.293-300
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• 2008

Muscle fat content including intramuscular fat content(IMF) is the most important parameter in meat quality of cattle. Triacylglycerol is the major component of fat and is found in adipocyte and skeletal muscle. In present study, we carried out the determined of triacylglycerol contents and mRNA expression patterns of genes related with triacylglycerol biosynthesis such as ACSS2, GPAT, MGAT and DGAT in Hanwoo longissimus muscle using the real-time PCR. The triacylglycerol contents were continuously increased during the fattening stages. Interestingly, the contents of triacylglycerol were 7.4 fold higher(0.34 vs. 2.51, P<0.01) in 27 months old group than 12 months old group. The mRNA levels of ACSS2, GPAT and DGAT genes were also increased during fattening stages, whereas that of MGAT gene did not show difference among the stages. Thus, these results suggested that increasing of the triacylglycerol contents in longissimus muscle during fattening stages may be related with increased expressions of triacylglycerol biosynthesis genes(ACSS2, GPAT and DGAT). These results will be helpful to understand the mechanism of muscle fat deposition in skeletal muscle.