Basic hematologic values in gilts of the Large White breed and their crosses with the Landrace breed

The basic haematological parameters (erythrocytes, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, leucocytes, leucocyte type) were determined in 83 clinically relatively healthy gilts of the Large White breed and 85 gilts--crossbreds with the Landrace breed, at the age of five to seven months. The results were subjected to statistical processing. The erythrocyte counts are significantly higher in the crossbreds than in the gilts of the LW breed. The basic erythrocyte values, dependent on the number of erythrocytes, are significantly higher in the gilts of the Large White breed. The leucocyte counts correlate with those of the gilts of the same age; however, they are higher than in the adult sows. As a result of the evaluation of the leucocyte type, the gilts at the age of five to seven months were found to have a white blood picture of lymphocytic type. Further, a shift towards younger forms of cells of the granulocytic series was observed even in clinically relatively healthy animals.     

Nutritional parameters in the blood of dams during late gestation and immediately after calving,in the umbilical vein at calving,and in the blood of calves immediately following birth in Holstein heifers pregnant with either Holstein or beef breed fetuses

Dairy cattle management lacks consideration of fetal breed, the effect of which on fetal growth and nutrition are unclear. We investigated blood parameters in 12 late-pregnant Holstein heifers with similar (Holstein, n = 5) or different (Japanese Black [n = 4] or F1 cross [n = 3]; Holstein × Japanese Black) fetus breeds and in their umbilical cords and calves. Samples were obtained from dams 1 week before calving (−1 week) and immediately after calving, from the umbilical vein at calving, and from calves immediately after birth. Dams with beef fetuses had higher serum glucose levels (−1 week; p < .05) than those with Holstein fetuses. Plasma total amino acid, total essential amino acid, total nonessential amino acid, and other amino acid concentrations were lower in the umbilical veins of dams with calves of the beef breeds than in those of the Holstein breeds (p < .05). Furthermore, serum glucose and plasma amino acid levels were lower in the beef calves than in the Holstein calves (p < .05). Overall, nutrient supply from dams to beef fetuses was lower than that to Holstein fetuses. Our findings may facilitate feeding management of dairy cattle pregnant with beef breeds for appropriate fetal growth and nutrition.     

Cellular and enzyme-histochemical aspects of adipose tissue development in obese (Ossabaw) and lean (crossbred) pig fetuses: an ontogeny study

The cellular and enzyme-histochemical differentiation of subcutaneous adipose tissue was studied in lean and obese pig fetuses at several ages. Positive reactions for a variety of cytosolic and organellar enzyme markers indicate metabolic competence of fetal adipocytes despite their small size (12 to 15 microns). Reactions for several enzymes decreased with fetal age and may be associated with a qualitative change in activity of adipocyte organelles. Age-associated increases in two lipogenic enzymes were observed in obese adipocytes. Observations on developing cells around hair follicles in the younger fetuses indicated significant temporal lags between the appearance of detectable enzyme activities in adipocytes. Enzyme activities in order of appearance were: dehydrogenases (cytosolic and mitochondrial), lipoprotein lipase and esterase. Esterase activity and several other enzymes were never observed in lipid positive cells that were not spherical. A proportion of hair follicle associated adipocytes in 110-d-old lean fetuses were histochemically and morphologically similar to brown adipocytes in the young rat. There was no evidence for brown adipocyte like cells in obese fetuses. Finally, comparison of the enzyme-histochemical differentiation of lean and obese fetal adipocytes indicates that fetal adipocytes become sensitive to external stimuli between 70 and 90 d of gestation.     

A retrospective analysis of allele frequency changes of major genes during 20 years of selection in the Italian Large White pig breed

In this study, we investigated whether a selection programme based on boar genetic evaluation obtained with a classical BLUP animal model can change allele frequencies in a pig population. All Italian Large White boars born from 1992 to 2012 with estimated breeding value reliability >0.85 (n = 200) were selected among all boars of this breed. Boars were genotyped with markers in major genes (IGF2 intron3‐g.3072G>A, MC4R p.D298N, VRTN PRE1 insertion, PRKAG3 p.I199V and FTO g.276T>G). Genotyping data were analysed grouping boars in eight classes according to their year of birth. To evaluate the influence of time on allele frequencies of the genotyped markers, multinomial logistic regression models were computed. Four of five polymorphic sites (IGF2, MC4R, VRTN and FTO) showed significant (p < 0.01) changes in allele frequencies over time due to a progressive and continuous increase of one allele (associated with higher lean meat content, higher average daily gain and favourable feed: gain ratio) and, consequently, decrease of the other one, following the directional selection of the selection programme of this pig breed. The retrospective analysis that was carried out in Italian Large White boars suggests that selection based on methodologies assuming the infinitesimal model is able to modify in a quite short period of time allele frequencies in major genes, increasing the frequency of alleles explaining a relevant (non‐infinitesimal) fraction of the overall genetic variability for production traits.     

Morphometric and ultrastructural changes in ciliated cells of the oviductal epithelium in prolific Chinese Meishan and Large White pigs during the oestrous cycle.

There are some differences in reproductive features between the Chinese Meishan (CM) pig and Large White (LW) pig. The aim of the present study was to investigate the quantitative changes and ultrastructural features of ciliated cells in the various regions of the CM and LW pig oviduct during the follicular and luteal phases of the oestrous cycle. In the fimbrial and ampullar epithelia at the follicular phase, the ciliated cells were more plentiful than in the isthmic region in both pigs. In the CM pigs, there was a striking decrease in the percentage and cell height of ciliated cells in the luteal phase compared with the follicular phase. Although similar quantitative changes were observed in the LW pig oviduct, these changes were less dramatic than that in the CM pig oviduct. In both pigs, the percentage and cell height of ciliated cells in the isthmus were unchanged between the follicular and luteal phases. The ultrastructure of ciliogenic and ciliated cells was observed. In the fimbrial and ampullar epithelia during the follicular phase, most of the ciliated cells showed normal morphology, having many elongated cilia and mitochondria, but in the CM pig oviduct during the luteal phase many of the ciliated cells possessed immature cilia and swollen mitochondria. Cells undergoing ciliogenesis were frequently observed in the fimbriae and ampulla, and occasionally in the isthmus. Cytoplasmic protrusions containing variable numbers of ciliary axonemal complexes occurred in the fimbrial and ampullar epithelium in the CM pigs at the luteal phase, suggesting that deciliation of cells occurs by membrane-bound cilia packets forming at the apices of cells and pinching off. These results demonstrate that there are regional variations in the cyclic changes associated with the oviductal ciliated cells of the pigs, while there are marked morphometrical and ultrastructural changes in oviductal ciliated cells of the CM pigs compared with that of the LW pigs.     

Plasma levels of cortisol in zero-weaned and lactating sows during the first two weeks post partum

The object of this investigation was to study the plasma levels of cortisol during the day of parturition and the first two weeks post partum in primiparous zero-weaned (weaned within 12 hr after birth) and lactating sows. Fourteen primiparous sows were used. They were grouped as follows: group A, (3 sows) zero-weaned, ovulating; group B, (4 sows) zero-weaned, anovulatory; group C, (4 sows) lactating with normal litter size; group D, (3 sows) lactating with small litter size. The peripheral plasma levels of cortisol were determined by radioimmunoassay throughout the experimental period,The peripheral plasma levels of cortisol were significantly higher in the anovulatory than in the normally ovulating sows. The lactating sows had almost the same levels of cortisol as the zero-weaned sows with anovulatory estrus. There was no difference in cortisol levels between sows nursing small or normal litters.It may be concluded that elevated plasma levels of cortisol might be one of several factors inhibiting the LH surge during the first estrus after zero-weaning. No relationship was found between cortisol levels and number of suckling piglets.     

Cellularity and enzymatic activity of adipose tissue in the Karagouniko dairy breed of sheep from birth to maturity

SUMMARY: The cellular and enzymatic characteristics of dissected subcutaneous and perirenal adipose tissues were examined in a total of 102 male and female animals from commerical flocks of the Karagouniko dairy sheep. The animals were slaughtered in groups of three males and three females at 45-day intervals from birth to 720 days of age. The following determinations were made on each animal: (1) subcutaneous and perirenal chemical fat, (2) fat cell size and number and (3) the activities of NADP-isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase in subcutaneous and perirenal adipose tissues. Subcutaneous adipose tissue expanded by a combination of fat cell hypertrophy and hyperplasia during the accelerating phase of the growth curve of chemical fat, after which the fat expansion was accomplished primarily by hyperplasia. The changes in perirenal chemical fat weight with increasing age were primarily due to hypertrophy of fat cells during the accelerating phase of the curve of chemical fat growth and due to a combination of hypertrophy and hyperplasia during the diminishing phase of the curve. The enzyme activities were higher in subcutaneous than in perirenal adipose tissue, with the NADP-isocitrate dehydrogenase being the most active enzyme in both tissues and sexes. The changes in enzyme activities in subcutaneous adipose tissue with increasing age were parallel to the changes in the rate of chemical fat weight during growth. ZUSAMMENFASSUNG: Zellularitaet und enzymatische Aktivitaet des Fettgewebes beim Karagouniko Milchschaf von der Geburt bis zur Reife. Es wurden die Anzahl und die Groesse der Fettzellen sowie die Aktivitaeten der NADP-Isocitrat-Dehydrogenase und der 6-Phosphogluconat Dehydrogenase in subcutanen und perirenalen Fettgewebe des Schafes waehrend des Wachstums undersucht. Das Tiermaterial bestand aus 51 maennlichen und 51 weiblichen Schafen der Karogouniko Milchrasse. Die Schafe wurden in Gruppen bestehend aus 3 maennlichen und 3 weiblichen Tieren in 45-taegigen Abstaenden von der Geburt bis zum Alter von 720 Tagen geschlachtet. Es wurden die folgenden Merkmale erfasst: Chemisches Fett, Anzahl and Groesse der Fettzellen, Aktivitaeten der gennanten Enzyme. Das subcutane Fettgewebe wuchs durch eine Kombination von Hypertrophie und Hyperplasia waehrend der beschleunigten Phase der Wachstumskurve fuer das chemische Fett. Nach dieser Wachstumsphase, das weitere Wachstum des subcutanen Fettgewebes kam vorwiegend durch Hyperplasia der Fettzellen zustande. Das perirenale Fettgewebe wuchs zunaechst durch Hypertrophie der Fettzellen und anschliessend durch eine Kombinationn von Hypertrophie und Hyperplasia. Die Aktivitaet der NADP-Isocitrat-Dehydrogenase war hoeher als die Aktivitaet der 6-Phosphogluconat-Dehydronase in beiden Geweben und Geschlechtern waehrend der gesamten Versuchsdauer. Die Aenderungen der Enzymaktivitaet waehrend des Wachstums stimmten gut ueberein mit den entsprechenden Aenderungen der taeglichen Wachstumstrate der subcutanen Fettgewebes.     

Effects of dietary glucose level during late gestation on litter performance and glucose concentration in sows

The effects of feeding glucose during the 5 days before parturition on litter performance and on glucose concentration in sows were studied. At day 100 of gestation, 130 multiparous sows were assigned to the treatments. Late gestating sows were fed 0 g, 150 g, 250 g, 350 g and 450 g of glucose a day, respectively. During lactation, all sows were given free access to the same lactation diet (without glucose). One day before parturition, blood samples were collected from 30 sows (6 sows per treatment) at 10 before and 20, 40, 60 and 80 min after the meal. The supply of additional dietary glucose increased piglet birth weight ( P  < 0.05). Feed intake in week 1 and week 1–4 of lactation was greatest in sows fed the 0% glucose diet, least by sows fed the 18% glucose diet, and intermediate by sows fed the 6, 10, 14% glucose diets ( P  < 0.05). Basal glucose concentration and time of maximum glucose concentration after glucose intake were not affected by dietary treatment in the last 5 days of gestation. The sows fed the 14 and 18% glucose diets had greater maximum increase in glucose concentration than sows fed diet without glucose ( P  < 0.05). In conclusion, feeding glucose to sows during 5 days before parturition increased birth weight of live-born piglet and decreased sows feed intake during lactation, but did not affect the performance of sows and piglets.     

Cellularity of developing subcutaneous adipose tissue in Landrace and Meishan pigs: Adipocyte size differences between two breeds

Experiments were designed to compare the adipocyte cellularity of subcutaneous adipose tissue between growing Landrace (low backfat) and Meishan (high backfat) pigs at 1 week, 3 weeks, 6 weeks, 3 months and 5 months of age. As pigs aged, body weight and backfat thickness of both breeds significantly increased. When compared at equal ages, backfat thickness adjusted to equal body weight was greater for Meishan pigs. The mean diameter of fat cell size also increased with age, and by 6 weeks adipocytes from both outer and inner layers of subcutaneous adipose tissue were larger in Meishan pigs. At 5 months, approximately 80% of the adipose tissue mass in Meishan pigs was attributable to adipocytes measuring 95–165 µm in diameter, whereas adipocytes of 75–145 µm comprised most of the tissue mass in the Landrace. Although the contribution of smaller adipocytes (25–45 µm) to the tissue volume was negligible, both breeds showed a biphasic diameter distribution at all ages, suggesting that adipocyte hyperplasia is still active. Our results demonstrate that cellularity differences exist between the subcutaneous adipose tissues of Landrace and Meishan pigs, and adipocyte hypertrophy is the most overwhelming contributor to the greater backfat deposition for Meishan pigs.     

后非洲猪瘟时期洋三元（DLY）商品母猪作种用的可行性分析及建议

自从2018年非洲猪瘟在中国暴发以来,为了尽快恢复产能,我国很多猪场在生产上开始采用洋三元商品母猪留作种用。通过收集某大型猪场的二元（（LY）母猪和洋三元（DLY）商品母猪的生产记录,统计两者在生产成绩上的差异,并综合其他文献来分析洋三元商品母猪留作种用的优缺点,给出改进的措施,为后非洲猪瘟时期养猪生产提供参考。     

Evidence for functional G-coupled protein receptors 43 and 120 in subcutaneous and intramuscular adipose tissue of Angus crossbred steers

We conducted 3 independent experiments to demonstrate functional G-coupled protein receptor 43 (GPR43) and GPR120 in bovine intramuscular (i.m.) and subcutaneous (s.c.) adipose tissues. We hypothesized that media volatile fatty acids and long-chain fatty acids would affect cAMP-activated protein kinase-alpha (AMPKα) protein expression and cAMP concentrations differently in i.m. and s.c. adipose tissue. Experiment 1: oleic acid (18:1n-9) decreased phosphorylated AMPKα protein (p-AMPKα) and the p-AMPKα/AMPKα protein ratio in i.m. preadipocytes, increased the p-AMPKα/AMPKα protein ratio in bovine satellite cells, and had no effect in s.c. preadipocytes. Experment 2: ex vivo explants from the 5th to 8th longissimus thoracic rib muscle section of Angus crossbred steers were cultured 48 hr in media containing 0.25 µM ciglitizone, 5 mM glucose, and 5 mM acetate, in the absence or the presence of 100 µM oleic acid. Oleic acid increased acetate incorporation into fatty acids and GPR43 gene expression in i.m. adipose tissue (P < 0.05), but oleic acid had no effect on fatty acid synthesis or GPR43 expression in s.c. adipose tissue. Experiment 3: fresh s.c. and i.m. adipose tissue from the 5th to 8th longissimus thoracic rib muscle section of Angus crossbred steers was transferred immediately to 6-well culture plates containing 3 mL of KHB/Hepes/5 mM glucose. Samples were preincubated with 0.5 mM theophylline plus 10 μM forskolin for 30 min, after which increasing concentrations of acetate or propionate (0, 10⁻³, 10^−2.3, and 10⁻³ M) in the absence or the presence of 100 μM oleic acid or 100 µM palmitic acid (16:0) were added to the incubation media. Acetate had no effect on forskolin-stimulated cAMP production in s.c. adipose tissue but decreased cAMP in i.m. adipose tissue (P < 0.05); this indicates a functional GPR43 receptor in i.m. adipose tissue. The combination of 10⁻² M acetate and oleic acid decrease cAMP production in s.c. adipose tissue, consistent with GPR120 receptor activity, but oleic acid and palmitic acid attenuated the depression of cAMP production caused by acetate in i.m. adipose tissue. Palmitic acid depressed cAMP production in s.c. adipose tissue, and increased cAMP production in i.m. adipose tissue (P < 0.05). Propionate had no effect on cAMP production in s.c. or i.m. adipose tissue. These results provide evidence for functional GPR43 receptors in i.m. adipose tissue and GPR120 receptors in s.c. adipose tissue, both of which would suppress lipolysis.     

Effects of low and high levels of maternal nutrition consumed for the entirety of gestation on the development of muscle,adipose tissue,bone, and the organs of Wagyu cattle fetuses

This study aimed to investigate the effects of high and low levels of energy intake during the entire gestation period on the skeletal muscle development, organ development, and adipose tissue accumulation in fetuses of Wagyu (Japanese Black) cows, a breed with highly marbled beef. Cows were allocated to a high-nutrition (n = 6) group (fed 120% of the nutritional requirement) or low-nutrition (n = 6) group (fed 60% of the nutritional requirement). The cows were artificially inseminated with semen from the same sire, and the fetuses were removed by cesarean section at 260 ± 8.3 days of fetal age and slaughtered. The whole-body, total muscle, adipose, and bone masses of the fetal half-carcasses were significantly higher in the high-nutrition group than the low-nutrition group (p = 0.0018, 0.009, 0.0004, and 0.0362, respectively). Fifteen of 20 individual muscles, five of six fat depots, nine of 17 organs, and seven of 12 bones that were investigated had significantly higher masses in the high-nutrition group than the low-nutrition group. The crude components and amino acid composition of the longissimus muscle significantly differed between the low- and high-nutrition groups. These data indicate that maternal nutrition during gestation has a marked effect on the muscle, bone, and adipose tissue development of Wagyu cattle fetuses.     

Flavor supplementation during late gestation and lactation periods increases the reproductive performance and alters fecal microbiota of the sows

This study was conducted to evaluate the effect of flavor on reproductive performance and fecal microbiota of sows during late gestation and lactation. A total of 20 healthy Yorkshire sows were fed a corn-soybean basal diet unsupplemented or supplemented with 0.1% flavor compound from d 90 of gestation to 25 d post-farrowing, and then the piglets were weaned. The reproductive performance and the fecal microbiota of sows were analyzed. Compared with the controls, flavor supplementation in maternal diets increased (P < 0.05) weaning litter weight, litter weight gain, weaning body weight, and average daily gain of piglets. There was a trend of increase in the average daily feed intake of sows (P = 0.09) by maternal dietary flavor addition. The backfat thickness and litter size were not affected by flavor supplementation (P > 0.05). The 16S rRNA analysis showed that flavor supplementation significantly increased the abundance of Phascolarctobacterium (P < 0.05), but significantly decreased genera Terrisporobacter, Alloprevotella, Clostridium_sensu_stricto_1, and Escherichia-shigella (P < 0.05). Spearman correlation analysis showed that Phascolarctobacterum was positively correlated with the average daily feed intake of sows (P < 0.05), the litter weight gain and average daily gain of piglets (P < 0.05). In contrast, Clostridium_sensu_stricto_1 and unclassified_f__Lachnospiraceae were negatively correlated with the litter weight gain and average daily gain of piglets (P < 0.05). Taken together, dietary flavor supplementation improved the reproductive performance of the sows, which was associated with enhanced beneficial microbiota and decreased potentially pathogenic bacteria in the sows.     

Effects of dietary arginine supplementation during gestation and lactation on the performance of lactating primiparous sows and nursing piglets

A 2 x 2 factorial arrangement of treatments in a randomized block design was used to determine the effects of dietary Arg supplementation during gestation and lactation on the lactation performance of 38 first-parity sows. At 30 d of gestation, pregnant gilts were allotted based on BW to 1 of 2 diets supplemented with 1% L-Arg.HCl or 1.7% L-Ala (isonitrogenous control). After farrowing, sows were further allotted based on BW within previous gestation treatment groups to 1 of 2 lactation diets supplemented with 1% L-Arg.HCl or 1.7% L-Ala (isonitrogenous control). All gestation diets contained 3.1 Mcal/kg and 12.2% CP (as is) and were fed 2 kg/d in 2 equally sized meals, whereas all lactation diets contained 3.2 Mcal/kg and 18.6% CP (as is) and were fed ad libitum. Litter size was standardized to 10 piglets by cross-fostering within 24 h postfarrowing. On a weekly basis, BW and backfat (BF) thickness of sows, as well as piglet BW were measured, and blood and milk samples were obtained from the sows. Number of days from weaning to estrus and ADFI were also recorded. There were no differences in BW, BF thickness, ADFI, or days until return to estrus among treatment groups. There was no effect of the gestation diet or a gestation x lactation diet interaction on any parameter measured. On d 7 of lactation, plasma concentrations of Arg and insulin in sows, as well as concentrations of most AA in milk, were greater (P < 0.05) in response to Arg supplementation during lactation compared with the control. Weight gain of piglets from sows fed the Arg-supplemented diet during lactation was greater between d 0 and 7 (P < 0.01) and between d 0 and 21 (P < 0.05) of lactation compared with piglets from sows fed the control diet. Collectively, results from this study indicate the potential beneficial effects of dietary Arg supplementation in improving the lactation performance of first-parity sows.     

Effects of maternal nutrition and porcine growth hormone (pGH) treatment during gestation on endocrine and metabolic factors in sows, fetuses and pigs, skeletal muscle development, and postnatal growth

Prenatal growth is very complex and a highly integrated process. Both maternal nutrition and the maternal somatotropic axis play a significant role in coordinating nutrient partitioning and utilization between maternal, placental and fetal tissues. Maternal nutrition may alter the nutrient concentrations and in turn the expression of growth regulating factors such as IGFs and IGFBPs in the blood and tissues, while GH acts in parallel via changing IGFs/IGFBPs and nutrient availability. The similarity in the target components implies that maternal nutrition and the somatotropic axis are closely related to each other and may induce similar effects on placental and fetal growth. Severe restriction of nutrients throughout gestation has a permanent negative effect on fetal and postnatal growth, whereas the effects of both temporary restriction and feeding above requirements during gestation seem to be of transitional character. Advantages in fetal growth gained by maternal growth hormone treatment during early to mid-gestation are not maintained to term, whereas treatment during late or greatest part of gestation increases progeny size at birth, which could be of advantage for postnatal growth. This review summarizes the available knowledge on the effects of different maternal feeding strategies and maternal GH administration during pregnancy and their interactions on metabolic and hormonal (especially IGFs/IGFBPs) status in the feto-maternal unit, skeletal muscle development and growth of the offspring in pigs.     

Effects of restricted feeding in the growing and laying periods on the performance of White Leghorn by Australorp crossbred and White Leghorn strain cross chickens

1. The effects of restricted feeding in the rearing and laying periods on the performance of three White Leghorn cockerel by Australorp pullet crossbred strains and one White Leghorn strain cross were studied in two experiments.

2. After feeding ad libitum in the rearing period, mean body weights of the three crossbred strains at 20 weeks of age were 1.75, 1.66 and 1.55 kg and that of the White Leghorn strain cross was 140 kg. The differing restrictions during rearing reduced mean body weight at 20 weeks by 14 to 33% and increased the time to sexual maturity by 8 to 23 d.

3. All restriction regimes during rearing increased mean egg weight and tended to reduce mortality in the laying period. Optimum hen‐day egg number over 64 weeks of lay was obtained following mild restriction (14% body weight reduction) of the two heavier strains or ad libitum feeding of the lighter strains. Over 48 or 64 weeks of lay, egg number per hen housed (at 18 to 20 weeks of age) was optimised after moderately restricting (14 to 21% body weight reduction) the crossbred strains or feeding the White Leghorn strain cross ad libitum.

4. Over 64 weeks of lay, mortality was reduced from 19.3% to 10.5% in the lightest crossbred strain, in which a high proportion of deaths were associated with Marek's disease and lymphoid leucosis, by restriction during rearing.

5. Restricting food intake by 7 or 8% throughout the laying period reduced hen‐day and hen‐housed egg number and mean egg weight of all four strains. The reduction in hen‐day egg number associated with food restriction during lay was less for the heavier strains that had also been restricted during rearing.

6. Metabolisable energy intakes required to support maximum production over 64 weeks of lay were 1.23 to 1.36 MJ/d.     

梅山与长白母猪粪样微生物体外发酵八种纤维底物的特性比较

本研究旨在比较不同品种母猪(梅山猪与长白猪)粪样中微生物对不同纤维底物的体外降解能力,同时分析粪样中的主要纤维降解菌数量。采集梅山(n=5)和长白(n=5)母猪新鲜粪样作为发酵接种物,以果胶、纤维素、菊粉、麦壳、麸皮、木聚糖、玉米芯渣及苜蓿作为纤维底物进行体外发酵,测定产气量和发酵液挥发性脂肪酸(volatile fatty acid,VFA)浓度。粪样同时用于提取细菌总核酸,变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)和real-time PCR对菌群区系进行分析。体外发酵结果表明,从发酵后9 h至96 h结束,长白猪接种物各组的累积产气量、有机物校正产气量分别显著(P<0.05)和极显著(P<0.01)高于梅山猪,长白猪T_1/2和T_max显著低于梅山猪(P<0.05),且发酵终产物中乙酸和总VFA浓度显著高于梅山猪接种物(P<0.05),整个发酵过程中不同底物间累积产气量差异显著(P<0.05),累积产气量从高到低的组别依次为:菊粉>麸皮>果胶>苜蓿>麦壳>玉米芯渣>木聚糖>纤维素。DGGE分析表明,梅山与长白母猪粪样菌群图谱中存在许多共同条带。Real-time PCR定量分析表明,梅山母猪粪样中的总细菌的16S rRNA基因拷贝数显著高于长白母猪(P<0.05),而拟杆菌、产琥珀酸丝状杆菌、黄化瘤胃球菌和白化瘤胃球菌等纤维降解菌数量及其占总菌比例差异均不显著(P>0.05)。结果显示,尽管2个品种母猪粪样中纤维降解菌数量无显著差异,但是长白母猪粪样微生物体外发酵纤维底物的能力高于梅山母猪。     

Effect of breed on fatty acid composition and stearoyl-CoA desaturase protein expression in the Semimembranosus muscle and subcutaneous adipose tissue of cattle

The present study investigated (i) the effect of breed on the expression of stearoyl-CoA desaturase (SCD) protein and fatty acid composition in Semimembranosus muscle and subcutaneous adipose tissue of beef cattle and (ii) the relationship between SCD expression, cis-9, trans-11 conjugated linoleic acid (CLA) content, and monounsaturated fatty acid (MUFA) level. The study was conducted on the following breeds: Longhorn (L), Charolais cross with Holstein–Friesian (CX), Hereford (H), Belted Galloway (BG) and Beef Shorthorn (BS). Significant breed differences in the total fatty acid content, saturated fatty acid (SFA) level, MUFA and n−3 PUFA content were observed in subcutaneous adipose tissue but not in muscle. In the case of CLA, the breed differences were observed in both muscle and subcutaneous adipose tissue, with the highest level in L and the lowest level in H. In the case of subcutaneous adipose tissue, the breed with the highest CLA content (L) also had the highest SCD protein expression. The breed-specific pattern of SCD expression in subcutaneous adipose tissue was similar to the breed-specific pattern of one of the products of an SCD-catalysed reaction, C16:1 (BS < BG < H < CX < L). It has been concluded that (i) the mechanisms regulating SCD protein expression and CLA level in beef cattle are tissue-specific; (ii) breed-specific variations in SCD expression might contribute to breed variations in MUFA and CLA content in subcutaneous adipose tissue but not in Semimembranosus muscle.