Effects of clay on fat necrosis and carcass characteristics in Japanese Black steers

Twenty 10‐month‐old Japanese Black steers were used to evaluate the effects of clay on fat necrosis and carcass characteristics. Ten steers (Clay group) were fed the clay (50 g/day) during 10–30 months of age. The other 10 steers (Control group) were not fed it. There was no significant difference in body weight or average daily gain between the two groups (P > 0.05). The occurrence of fat necrotic mass in the Clay group (30%) was lower (P < 0.05) than that in the Control group (90%) at slaughter. The size of necrotic masses in the Clay group was smaller (P < 0.05) than that in the Control group. There was no significant difference in the marbling score, beef color, Longissimus muscle area or subcutaneous fat thickness between the two groups. These results suggest that the clay prevented the occurrence of fat necrosis and did not affect the carcass characteristics in Japanese Black steers.     

Variations in genes involved in fat metabolism and their association with ultrasonic and carcass traits in Japanese Black steers

Polymorphisms in genes involved in lipid metabolism have been reported to be associated with fatty acid composition of adipose tissue. However, the relationship of these polymorphisms with premortem ultrasonic traits is unknown. The objective of this study, therefore, was to assess the association between polymorphisms in fatty acid synthase, stearoyl‐coenzyme A desaturase (SCD), sterol regulatory element‐binding protein 1 (SREBP1), diacylglycerol acyltransferase 1, and nuclear receptor subfamily 1, group H, number 3 genes with ultrasonic and carcass traits in Japanese Black steers (n = 300) under progeny testing at the Livestock Improvement Association of Miyazaki. To have a comprehensive analysis of the association between the aforementioned genetic polymorphisms and ultrasonic traits, longitudinal measurements of ultrasonic traits were taken. Furthermore, the association of these genetic polymorphisms and carcass traits was evaluated. The polymorphisms in the SCD gene and SREBP1 were associated (P < 0.05) with some ultrasonic traits at multiple stages. To add to that, the polymorphisms were associated (P < 0.05) with some carcass traits. These findings suggest that the polymorphisms in SCD and SREBP1 are functional mutations or could be related to mutations that can aid in selection to improve some ultrasonic and carcass traits.     

Effect of fat content on sensory characteristics of marbled beef from Japanese Black steers

To analyze the sensory characteristics of meat samples with a crude fat content between 23.8% and 48.6% taken from 34 Japanese Black steers, we grilled the meat and subjected it to analytical sensory evaluation. We also measured the amounts of moisture, protein, nucleic acid and glutamic acid. An increase in crude fat content increased the tenderness, juiciness, and fattiness in the meat quality evaluation. An increase in crude fat content reduced the crude protein and moisture contents; it also slightly reduced the nucleic acid and glutamic acid contents, although when the reductions in these umami components were assessed relative to the moisture content they changed little. Increasing the fat content up to a certain point greatly enhanced the umami intensity and beef flavor intensity in the meat quality evaluation and raised the overall evaluation score; the peak of the appropriate crude fat content for these purposes was about 36%.     

Fat depot‐specific effects of body fat distribution and adipocyte size on intramuscular fat accumulation in Wagyu cattle

Ectopic fats have been recognized as a new risk factor for metabolic syndrome. In obese humans, ectopic fat accumulations are affected by body fat distribution. Intramuscular adipose tissue is categorized as one of the ectopic fats. Japanese black cattle (Wagyu) are characterized by the ability to accumulate high amounts of intramuscular adipose tissue. In Japan, the marbling level is indicated by the beef marbling standard number (BMS No.), which reflects the intramuscular fat content of longissimus muscle. We hypothesized that the intramuscular fat accumulation is affected by the body fat distribution in Wagyu cattle. In this study, we showed that the BMS No. was not correlated with the subcutaneous and visceral adipocyte diameter. In contrast, the BMS No. was positively correlated with intramuscular adipocyte diameter. These results indicate that the intramuscular adipocyte diameter of Wagyu is hypertrophied with an increase in the intramuscular fat accumulation. In addition, we showed that the BMS No. was positively correlated with the subcutaneous fat percentage. In contrast, the BMS No. was negatively correlated with the visceral fat percentage. These results indicate that highly marbled Wagyu cattle have a higher percentage of subcutaneous fat and a lower percentage of visceral fat.     

Effects of the fattening period on the fatty acid composition of fat deposits and free amino acid and inosinic acid contents of the longissimus muscle in carcasses of Japanese Black steers

The effects of the fattening period on carcass characteristics, fatty acid composition of fat deposits, and muscle free amino acid (FAA) and inosinic acid (IMP) contents were evaluated in Japanese Black steers. Ten castrated, 10-month-old calves derived from the same sire were divided into five to be slaughtered at the age of 30 months after a 20-month fattening period (20-month group) and five to be slaughtered at the age of 34 months after a 24-month fattening period (24-month group). Concerning the fatty acid composition of subcutaneous fat, the percentage of palmitoleic acid was higher ( P  < 0.05) in the 24- than in the 20-month group, but no difference was noted in any other fatty acids. For intermuscular fat, no difference was observed in any fatty acids. The percentages of oleic acid and total monounsaturated fatty acid of intramuscular and perinephric fat were higher ( P  < 0.05) in the 24- than in the 20-month group. Of the FAAs in the longissimus thoracis muscle, the threonine and tyrosine contents were lower ( P  < 0.05) in the 24- than in the 20-month group. The IMP content was higher ( P  < 0.05) in the 24- than in the 20-month group, suggesting an effect of prolongation of the fattening period.     

Effects of GH gene polymorphism and sex on carcass traits and fatty acid compositions in Japanese Black cattle

To investigate the effects of bovine growth hormone (bGH) gene polymorphism on carcass traits and fatty acid compositions in Japanese Black cattle caused by nucleotide substitution of CTG (allele A)/GTG (allele B) at codon 127 and of ACG (allele A and B)/ATG (allele C) at codon 172 of bGH, GH genotypes of 135 cattle were determined using allele specific-multiplex polymerase chain reaction (PCR). Allele A gave greater rib thickness and lower melting point of fat (MP) while allele B gave higher C18:1% ( P  < 0.05). Allele C gave higher C18:1, monounsaturated fatty acid (MUFA), unsaturated fatty acid (USFA) percentages ( P  < 0.05). It also gave lower saturated fatty acid (SFA) percentages, higher MUFA/SFA and USFA/SFA ratios, and lower MP ( P  < 0.05). Interactions of sex and GH alleles were analyzed. In heifers, allele A gave higher carcass weight, daily carcass gain, rib eye area, rib thickness, subcutaneous fat thickness, and BMS while allele B gave greater rib eye area and rib thickness ( P  < 0.05). Allele C gave higher C18:1 ( P  < 0.01), MUFA ( P  < 0.01), USFA percentages ( P  < 0.05) and MUFA/SFA and USFA/SFA ratios ( P  < 0.01), and lower C16:0 and SFA percentages ( P  < 0.05) and MP ( P  < 0.01). GH gene polymorphism affected carcass traits and fatty acid compositions although the effects were more pronounced in heifers.     

苏尼特羔羊肌内脂肪沉积规律及其与肌肉嫩度相关性的研究

本试验以苏尼特羊为研究对象,采用单因子试验设计,对不同屠宰体重(10、20、30kg和40kg)羔羊的日增重、屠宰率和肉质进行系统研究。试验结果表明:苏尼特羔羊的体重对日增重、屠宰率、肌肉水分含量、肌内脂肪含量、剪切力和系水率都有显著影响(P0.05);肌内脂肪含量与肌肉剪切力呈极显著负相关(r=-0.983,P0.01)。     

Effect of negative dietary cation‐anion differences on carcass characteristics and beef tenderness of Japanese Black steers

Lowering dietary cation‐anion differences (DCAD) can enhance responsiveness to Ca‐homeostatic hormones and increase Ca availability, which might have potential to activate a Ca‐dependent protease, calpain, and to enhance postmortem myofibrillar proteolysis. In this study, we investigated the effects of DCAD manipulation on calpain activity and beef tenderness in Japanese Black cattle which are characterized by their high marbling. Thirty‐six Japanese Black steers were allotted to one of two treatments: (i) control (CON; DCAD +6.09 mEq/100 g of dry matter (DM)) or (ii) negative DCAD (NEGD; DCAD ?8.27 mEq/100 g DM) for 70 days before slaughter. Lowering DCAD decreased DM and energy intake (P < 0.01) even though it did not negatively affect the growth performance or carcass characteristics. In NEGD, urine pH was decreased by acidification caused by the negative DCAD (P < 0.01). Calpain activities tended to be improved in NEGD (P = 0.09), but Warner‐Bratzler shear force values were not affected by treatment. Although calpain activities tended to improve, lowering DCAD to ?8.27 for 70 days before slaughter was insufficient to enhance beef tenderness in Japanese Black steers.     

Genomic imprinting variances of beef carcass traits and physiochemical characteristics in Japanese Black cattle

The objective of this study was to estimate variance components related to imprinting for carcass traits and physiochemical characteristics in Japanese Black cattle. The carcass records obtained from 4,220 Japanese Black feedlot cattle included carcass weight (CW), rib eye area (REA), rib thickness, subcutaneous fat thickness, and beef marbling score (BMS), and the physiochemical characteristics were fat, moisture, glycogen per proportion of moisture content, oleic acid, and monounsaturated fatty acids (MUFA). To detect gametic effects, an imprinting model was fitted. High additive heritabilities were estimated for all traits (from 0.516 for glycogen to 0.853 for fat) and were reduced in Mendelian heritability. The range of the differences was from 0.002 (CW) to 0.331 (fat and moisture), and the reductions were due to their imprinting variances. The ratio of the imprinting variance to the total additive genetic variance for REA (0.374), BMS (0.291), fat (0.387), moisture (0.388), and MUFA (0.337) were large (p < 0.05). These imprinting variances were due to the maternal contribution and suggested the existence of maternally expressed genomic imprinting effects on the traits in Japanese Black cattle. Therefore, maternal gametic effects should be considered in breeding programs for Japanese Black cattle.     

Increased ectopic fat cells in the longitudinal muscularis layer of the oviduct isthmus in obese Japanese Black cows

In obese humans, mesenchymal stem cells differentiate to become ectopic fat cells in muscles. These ectopic fat cells inhibit the contraction of vascular smooth muscles. Stem cells have been recently identified in the human oviduct, a structure important in reproduction. We therefore investigated the number of Oil Red O (ORO)‐positive cells in the oviducts of control Japanese Black cows (n = 6; body condition score [BCS], 3.0 on a 5‐point scale) compared to those with diet‐induced obesity (n = 5; BCS, 4.0). We stained the ampulla and isthmus collected on the second day after ovulation with ORO and then counted the positive cells in each layer in 10 cross‐sections of the ampulla or isthmus. The obese group (23.4 ± 3.4 in the 10 sections) had larger numbers of ORO‐positive cells in the longitudinal muscularis of the isthmus (P < 0.05) than did the control group (15.0 ± 2.4). ORO‐positive cells were also observed in all other layers of the isthmus and ampulla; however, the number of cells in these layers did not differ significantly between obese cows and controls. Whether this observed increase in ORO‐positive cells in the oviducts of obese cows affects their reproduction warrants further study.     

Effects of different levels of protein supplementary diet on gene expressions related to intramuscular deposition in early‐weaned yaks

This study was conducted to estimate different levels of protein supplementary diet on gene expressions related to intramuscular deposition in early‐weaned yaks. Results showed that supplementary dietary protein significantly increased final weight, average daily gain (ADG), intramuscular fat (IMF), serum free fatty acid (FFA), total triglycerides, total cholesterol (Ch), low‐density lipoprotein cholesterol (LDL) and high‐density lipoprotein cholesterol (HDL) content. There was a quadratic response of ADG, IMF, FFA, Ch, HDL and LDL to dietary crude protein (CP) level. Lipoprotein lipase (LPL), fatty acid synthase (FAS) and acetyl‐CoA carboxylase (ACC) enzyme activities were significantly increased by supplementary dietary CP, while hormone‐sensitive lipase (HSL) and carnitine palmitoyltransferase‐1 (CPT‐1) activities were significantly decreased. LPL, ACC and FAS enzyme activities showed quadratic increase as dietary CP increased. Peroxisome proliferator‐activated receptor γ (PPARγ), LPL, FAS, sterol regulatory element binding protein 1 (SREBP‐1), ACC, stearoyl‐CoA desaturase (SCD) and heart fatty‐acid binding protein (H‐FABP) gene expression were significantly increased by supplementary dietary CP, while HSL and CPT‐1 gene expression were significantly decreased. PPARγ, LPL, SREBP‐1, ACC and H‐FABP gene expression showed quadratic increase as dietary CP increased. These results indicated that supplementary dietary protein increased IMF accumulation mainly to increased intramuscular lipogenic gene expression and decreased lipolytic gene expression.     

Effects of wood kraft pulp feeding on feed digestibility and rumen fermentation of Japanese Black steer in the middle fattening stage

We investigated the effects of wood kraft pulp (KP) feeding on feed digestibility and rumen fermentation of Japanese Black (JB) steer in the middle fattening stage. The feeding experiment was carried out a replicated 3 × 3 Latin square design using six JB steers (16.2 ± 0.8 months of age). Steers were fed rice straw and three concentrated feeds: commercial formula feed (control), formula feed containing 7.5% KP on a dry matter (DM) basis (7.5% KP), and formula feed containing 15% KP on a DM basis (15% KP). Feed digestibility and rumen fermentation parameters were recorded for 3 days during the measurement period, after an adaptation phase of 11 days. There was no significant difference in DM intake per day among diets. A slightly higher digestibility of neutral detergent fiber was observed in steers fed 15% KP, compared with those fed other diets (P = 0.059). The butyric acid ratio in rumen fluid was higher in steers fed KP diets than in steers fed control (P = 0.083). The average ruminal pH was unaffected by KP diets. This study suggests that replacing 15% of concentrated feed with KP has little effect on feed digestibility and rumen fermentation in JB fattening steer.     

营养水平对荣昌猪肌内脂肪、脂肪酸含量的影响研究

试验选用84头10 kg左右荣昌阉公猪,随机分成2组,每组6个重复,每个重复7头猪,在参照中国瘦肉型猪饲养标准(高营养水平组)、荣昌猪(GB 7223—1987)饲养标准(低营养水平组)配制的2种日粮饲喂条件下,研究日粮营养水平对生长肥育期荣昌阉公猪肌内脂肪、脂肪酸含量及组成的影响。结果表明:本试验条件下,营养水平对生长育肥阶段荣昌猪肌内脂肪含量无显著影响;高营养水平组显著提高荣昌猪35 kg时硬脂酸含量(P0.05)和20 kg时亚麻酸含量(P0.05);荣昌猪的饱和脂肪酸、不饱和脂肪酸和必需脂肪酸含量,高低营养水平组在各个体重阶段差异均不显著(P0.05)。     

Relationships between mineral concentrations and physicochemical characteristics in the Longissimus thoracis muscle of Japanese Black cattle

The relationship between mineral concentrations, and the relationship of mineral concentrations with physicochemical characteristics in muscles were investigated using the Longissimus thoracis (LT) muscle of 44 Japanese Black steers. We determined moisture content, fat content, meat color, fatty acid composition and mineral concentrations in the LT muscle. Magnesium (Mg), potassium (K) and zinc (Zn) concentrations had negative correlations with fat content, but sodium (Na), manganese (Mn), copper (Cu) and molybdenum (Mo) concentrations were not correlated with fat content. The concentrations of Mg, Mn, Fe, Cu and Zn largely and positively contributed to the first principal component of mineral concentrations. Because the red muscle was rich in these minerals compared to the white muscle, the variation of these minerals probably results from the abundance of red fibers in the LT muscle. The concentration of K was positively correlated with moisture content but Na concentration was not related to moisture content, suggesting that the intracellular fluid volume can largely affect moisture content. The results of the present experiment suggest that mineral concentrations reflect some traits such as not only fat content but also the composition of myofiber type and the intracellular fluid volume in the LT muscle of Japanese Black cattle.     

Differences in the behavior of the crossbred steers of different sire lines of Japanese Black cattle

We determined differences in the behavior of the progeny of two major sire lines of Japanese Black cattle by recording the behavior of 35 and 70 half-sib steers of sires from fast (FG) and slow (SG) growing lines, respectively. Two sire lines of steers were mixed and allocated to nine pens with 11–12 animals per pen. The proportion of steers lying was significantly (P < 0.001) higher in the SG line (43.4 ± 5.7% compared to 40.3 ± 6.0%). The proportion of time spent eating concentrate feed (FG: 12.1 ± 2.3%; SG: 11.4 ± 2.1%), drinking (FG: 0.8 ± 1.1%; SG: 0.4 ± 0.6%), licking the feed trough (FG: 0.4 ± 0.6%; SG: 0.2 ± 0.4%) and performing tongue-playing (FG: 3.1 ± 4.6%; SG: 1.0 ± 1.9%) was significantly higher in FG, whereas the proportion of time spent resting (FG: 41.5 ± 12.8%; SG: 43.7 ± 10.9%) and performing self-licking (FG: 1.7 ± 1.4%; SG: 2.1 ± 1.3%) was higher in SG (all P < 0.05). These results show progeny of the FG sire engaged in more active behaviors compared to the progeny of the SG sire line.     

Effects of feeding different levels of concentrate on growth and carcass characteristics in younger Japanese Black cattle

The effects of a higher concentrate feed during the raising period on the growth and carcass of Japanese Black cattle being fattened at a younger age were investigated using three pairs of artificially bred identical twins and three pairs of full‐sibs. The animals were fed the concentrate at 2.4%/day (2.4% group) and 1.2%/day (1.2% group) comparative bodyweight (BW) during the raising period. The BW and subcutaneous fat thickness were measured every month using ultrasonic equipment. The animals were slaughtered at the age of 24 months. The BW of the 2.4% group from the age of 6–10 months appeared to be higher than that of the 1.2% group (P < 0.1). The subcutaneous fat of the 2.4% group from the age of 7–11 months was thicker than that of the 1.2% group (P < 0.1). After those ages, the BW and subcutaneous fat of the two groups did not differ and there was no difference in the carcass characteristics between the two groups. Using a higher concentrate feed during the raising period for younger fattening of Japanese Black cattle influenced growth from the late half of the raising period to the early part of the fattening period.     

Effects of dietary lysine levels and lighting conditions on intramuscular fat accumulation in growing pigs

This study was conducted to test our hypothesis that intramuscular fat (IMF) accumulation increases in pigs fed on a low lysine diet during the dark period than those fed on the same diet during the light period. Using barrows aged 6 weeks, we monitored whether serum glucose and insulin levels were affected by light conditions. Two diets with different levels of lysine, 0.78% (LL diet) and 1.37% (control diet) were prepared. Eight pigs were fed on the diet during the light period, while the remaining pigs were fed during the dark period. The pigs were fed either the LL diet or the control diet. Although IMF contents of Longissimus dorsi (LD) muscle were higher in the pigs fed on a LL diet (p < .05), the light conditions had no effect. Low dietary lysine caused reduction in serum glucose levels (p < .05) and serum insulin levels (p = .0613). However, they were also unaffected by the lighting conditions. To gain further insights, we determined the messenger RNA levels of insulin receptor, insulin receptor substrate 1, acetyl CoA carboxylase, and fatty acid synthase in LD and Rhomboideus muscles and in the liver.     

Effects of probiotic Bacillus cereus toyoi on abdominal fat accumulation in the Japanese quail (Coturnix japonica)

Effects of a commercial probiotic, Bacillus cereus toyoi on abdominal fat accumulation in the Japanese quail fed either a commercial control diet (crude protein (CP), 23.5%; metabolizable energy (ME), 11.7MJ/kg) or a high‐energy diet (CP, 23.0%; ME, 13.8MJ/kg) were investigated. Four‐week‐old male birds (n = 108) were divided into four diet groups: control diet, control with probiotic, high‐energy diet and high‐energy diet with probiotic. At 8 weeks and 12 weeks of age (4 and 8 weeks of probiotic supplementation period, respectively), abdominal fat, muscles and the liver were weighed. The weight of total fat and protein in the muscles and liver were also determined. A rectal temperature was recorded weekly. Bodyweight and feed intake in both diets were not affected by probiotic supplementation. At 8 weeks of age, birds fed the control diet with probiotic had significantly less abdominal fat than those fed without the probiotic, and a similar tendency was seen for both diet groups at 12 weeks of age. The decrease in abdominal fat coincided with an increase in rectal temperature. These results suggest that greater metabolizable energy was consumed through elevation of heat production by supplementation of B. cereus toyoi, with hardly any energy stored as body fat. Probiotic supplementation appears to induce greater muscle weight, higher protein and lower lipid content in muscles by 8 weeks of age, and lower lipid content in muscles and greater liver weight by 12 weeks of age, in the Japanese quail.     

Effects of parent‐of‐origin models with different pedigree information on beef carcass traits and fatty acid composition in Japanese Black cattle

Genomic imprinting should be considered in animal breeding systems to avoid lead in bias in genetic parameter estimation. The objective of this study was to clarify the effects of pedigree information on imprinting variances for carcass traits and fatty acid composition in Japanese Black cattle. Carcass records [carcass weight, rib eye area, rib thickness (RT), subcutaneous fat thickness and beef marbling score (BMS)] and fatty acid composition were obtained for 11,855 Japanese Black feedlot cattle. To estimate and compare the imprinting variances for the traits, two imprinting models with different pedigree information [the sire–dam gametic relationship matrix (Model 1) and the sire–maternal grandsire (MGS) numerator relationship matrix (Model 2)] were fitted. The ratio of the imprinting variance to the total additive genetic variance for RT (6.33%) and BMS (19.00%) was significant in Model 1, but only that for BMS (21.09%) was significant in Model 2. This study revealed that fitting the sire–MGS model could be useful in estimating imprinting variance under certain conditions, such as when restricted pedigree information is available. Furthermore, the present result suggested that the maternal gametic effects on BMS should be included in breeding programmes for Japanese Black cattle to avoid selection bias caused by imprinting effects.