Rongzhen Zhong

The effects of road transportation on physiological responses and meat quality in sheep differing in age

The aim of this study was to determine the effects of 8 h of road transportation on physiological responses and meat quality traits of sheep at 6, 12, and 24 mo of age. Seventy-two male sheep were equally divided into transported (TRANS) and nontransported (CON) treatments (n = 36), and each treatment was subdivided into 3 groups by age (n = 12). Sheep in CON groups were weighed, blood sampled, and slaughtered, whereas sheep in TRANS groups were weighed, transported, blood sampled, and slaughtered to collect meat samples. The BW of sheep in TRANS groups was reduced significantly (P < 0.001) compared with CON sheep, and older sheep lost more BW than younger animals. However, dressing percentages of TRANS sheep were significantly (P < 0.001) greater than those of CON sheep. Some meat quality variables were affected by transportation, and responses of different ages of sheep varied. Total pigment content and lipid oxidation of LM and gluteus medius of TRANS sheep increased significantly (P < 0.001) compared with CON sheep. Cooking loss of LM and gluteus medius was influenced significantly (P < 0.01) by interaction effect between transportation and age, and the values for 6-mo-old TRANS sheep were less than those of CON sheep. Serum total protein (P = 0.036), globulin (P = 0.026), triglyceride (P < 0.001), and total cholesterol concentrations (P = 0.028) of TRANS sheep decreased compared with CON sheep. Serum NEFA concentration of TRANS sheep increased in relation to CON sheep with a significant interaction (P < 0.001) between transportation and age effect. Numbers of white blood cells were influenced (P = 0.002) by an interaction effect between transportation and age, and values for 6-mo-old sheep were not influenced by transportation. Numbers of platelets were influenced (P = 0.014) by age; they decreased more in 6-mo-old sheep than in older sheep. Transportation and age had no significant effects (P > 0.05) on packed cell volume and lymphocyte number. Serum creatine kinase activities in TRANS sheep were affected (P = 0.01) by an interaction effect between transportation and age. The 2-thiobarbituric acid reactive substances in serum of TRANS sheep increased (P = 0.009) with the greatest change for 6-mo-old compared with older sheep. In conclusion, 8 h of road transportation resulted in greater heme pigment concentrations but improved meat tenderness and induced physiological responses of sheep. However, different ages of sheep showed different responses to the present transportation pattern.

Effect of Tea Catechins on Regulation of Antioxidant Enzyme Expression in H2O2-Induced Skeletal Muscle Cells of Goat in Vitro

Skeletal muscle cells (SMCs) of goats were stress induced with 1 mM H(2)O(2) in the absence or presence of 0.5, 5, and 50 μg/mL tea catechins (TCs) incubation. Cells were harvested at 48 h postincubation with TCs to investigate the effects of TCs on cell proliferation, cell membrane integrity, antioxidant enzyme activities, and antioxidant enzyme genes and protein expression levels. Results showed that H(2)O(2) induction inhibited cell proliferation with or without TC incubation; moreover, the inhibition effect was enhanced in the presence of TCs (P < 0.001). H(2)O(2)-induced stress increased the lactate dehydrogenase (LDH) activity in the absence or presence of TC incubation, but concentrations of TCs, less than 5 μg/mL, showed protective functions against LDH leakage than in other H(2)O(2)-induced treatments. The catalase (CAT) activity increased when SMCs were stress induced with H(2)O(2) in the absence or presence of TC incubation (P < 0.001). H(2)O(2)-induced stress decreased CuZn superoxide dismutase (CuZn-SOD) and glutathione peroxidase (GPx) activities, whereas this effect was prevented by incubation with TCs in a concentration-dependent manner. H(2)O(2)-induced stress with or without TC incubation had significant effects on mRNA and protein expression levels of CAT, CuZn-SOD, and GPx (P < 0.001). CAT and CuZn-SOD mRNA expression levels were increased by different concentrations of TC incubation, and this tendency was basically consistent with corresponding protein expression levels. The GPx mRNA expression level increased with a low concentration of TCs but decreased with concentrations greater than 5 μg/mL of TCs, whereas GPx protein expression in all TC-incubated groups was lower than in the control treatment. The current findings imply that TCs had an inhibitory effect on cell proliferation and enhanced damage to the cell membrane integrity, but TCs affected antioxidant status in SMCs by modulating antioxidant enzyme activities at mRNA and protein expression levels.

Effects of lairage time after road transport on some blood indicators of welfare and meat quality traits in sheep

The study was conducted to evaluate the effects of different lairage time after 8 h road transport on some blood indicators of welfare and meat quality traits in sheep. A total of 84 Ujimqin male sheep (average body weight 27.5 kg, 6 months old) were randomly allotted to one of seven groups: one control group (untransported) and six lairage groups (8 h road transport with 0, 2, 6, 12, 24 and 48 h lairage times respectively). No significant lairage time effects were observed on weight loss. Sheep in 48 h group showed lower hot carcass weight, dressing percentage and higher pH(24 h) than that in other groups. The total haem pigment contents in sheep meat rose and were higher in 24 and 48 h groups than that in the control group. After transport, sheep in 0, 2, 24 and 48 h groups showed higher serum creatine kinase activities, cortisol and glucose concentrations than that in control group. Sheep in lairage groups had higher serum triiodothyronine and thyroxine levels compared with the control sheep. Sheep in 48 h group showed significant higher packed cell volume, total protein and blood urea nitrogen than that in other groups. Compared with the control group, the white blood cell counts were higher in 0 and 48 h groups. The neutrophil counts in 24 or 48 h groups were higher than that in the control group. The opposite was true for lymphocyte counts. A 6-12 h lairage is recommended in terms of the present transported pattern.

Effects of Substitution of Different Levels of Steam-Flaked Corn for Finely Ground Corn on Lactation and Digestion in Early Lactation Dairy Cows

Eight multiparous Holstein cows, 4 of them fitted with rumen cannulas, were used to test the effects of substitution of steam-flaked corn (SFC) for equal amounts of finely ground corn (FGC) in diets on feed intake and digestion, blood metabolites, and lactation performance in early lactation dairy cows. Cows were fed 4 diets in a replicated 4 x 4 Latin square design. The fistulated cows formed 1 replicate. Each experimental period lasted for 3 wk. The 4 diets contained 0, 10, 20, or 40% SFC and 40, 30, 20, or 0% FGC (dry matter basis), respectively. The milk protein content and yield, milk solid nonfat content and yield, plasma glucose concentration, and dry matter intake increased as the proportion of SFC increased in diets. Apparent total tract digestibilities of dry matter, organic matter, neutral detergent fiber, acid detergent fiber, and average ruminal fluid NH(3)-N concentration decreased with increasing levels of SFC. The ruminal fluid pH was not affected by the substitution of SFC for FGC. The 20% SFC substitution improved digestion of crude protein, yield of fat-corrected milk, milk lactose content, fat, and fat yield. The 40% SFC substitution increased urea concentration in both plasma and milk. It was concluded that 20% of SFC substitution for FGC appeared to be an appropriate level in diet for early lactation dairy cows.

Effects of dietary supplementation with green tea polyphenols on digestion and meat quality in lambs infected with Haemonchus contortus

Ujumqin sheep are susceptible to infection by the gastrointestinal nematode Haemonchus contortus, which reduces productivity and total meat yield in sheep. Thus, the effects of green tea polyphenol (GTP) supplements (0, 2, 4, or 6g of GTP/kg feed) on dietary nutrient digestibility and meat quality in lambs infected with H. contortus were examined; control lambs were not infected. H. contortus infections did not affect digestion but the apparent digestibilities of nutrients were decreased by dietary 2g of GTP/kg feed supplementation. There was an interaction between treatment and sampling time on plasma total protein, urea nitrogen, and amino acid concentrations. The antioxidant activity and meat color of INFGTP0 lambs decreased. In conclusion, H. contortus infections in lambs decreased meat quality, but appropriate levels of dietary GTP supplementation diminished these negative effects though lower dose of GTP supplement showed negative effects on digestion.

Meat quality, fatty acid composition of tissue and gastrointestinal content, and antioxidant status of lamb fed seed of a halophyte (Suaeda glauca)

Twenty-four Merino lambs were randomly assigned to four treatments: control diet (CT) consisting of 300g concentrates with ad libitum Leymus chinensis hay; C with 150g (T150), 300g (T300) and 450g (T450) Suaeda glauca seed, respectively. Meat quality, fatty acid composition of meat and lipid tissue and antioxidant status of lamb were evaluated. Inclusion of S. glauca seeds significantly increased selenium (Se) concentrations of muscle. The proportions of C18:1 trans-11 in muscle, C18:2 n-6, PUFA, n-6 series fatty acids, and the ratios of P:S in rumen contents, as well as the ratios of n-6:n-3 in adipose tissue, rumen and duodenum content have been significantly (P<0.05) improved with supplementation of S. glauca seeds to lamb diets. No significant effect was found on antioxidant status. The results suggest that S. glauca seed supplementation in lamb diets may change fatty acid composition in tissues and content of digestive tract.

Effects of tannic acid on Haemonchus contortus larvae viability and immune responses of sheep white blood cells in vitro

Direct inhibitory effects of tannic acid on Haemonchus contortus viability were studied in vitro using the larval migration inhibition (LMI) assay. Sheep white blood cells (WBC) were preincubated with 5 and 50 μg/mL tannic acid or not followed by whole H. contortus antigen (WHA). Cells were harvested at 24 h post‐incubation to test host immune responses. Concentrations of 50, 100, 500, 1000, 3000 and 5000 μg/mL tannic acid inhibited larvae migration by 19·8, 42·4, 46·3, 92·0, 93·7 and 100%, respectively, within 96 h post‐incubation (P < 0·001). The relative mRNA levels of interferon (IFN)‐γ, interleukin (IL)‐2, IL‐4 and IL‐10 were increased by WHA stimulation without tannic acid. However, the increased effects on IFN‐γ and IL‐2 were inhibited by tannic acid preincubation (P < 0·001), while the increases in IL‐4 and IL‐10 were greatly enhanced by tannic acid preincubation (P < 0·001). Changes in protein levels of all cytokines essentially paralleled the changes in their corresponding mRNA levels. In conclusion, tannic acid is directly harmful to larvae in a dose‐ and time‐dependent manner and modulates immune responses of sheep WBC stimulated by H. contortus antigen by inhibiting Th1 cytokines and increasing Th2 cytokine expression in vitro.

Global DNA methylation and related mRNA profiles in sheep oocytes and early embryos derived from pre-pubertal and adult donors

The developmental capacity of in vitro-matured oocytes and in vitro-fertilized embryos from pre-pubertal sheep is less than that of adult counterparts, and epigenetic mechanisms are thought to be involved. In the present study, germinal vesicle stage oocytes were collected by follicular aspiration from superovulated 4-week-old lambs and 2.5-year-old ewes. There were evaluations of the developmental potential of oocytes and embryos by in vitro culture and fertilization, global DNA methylation and hydroxymethylation patterns by immunofluorescence staining, and relative abundance of enzyme mRNA by quantitative real-time polymerase chain reaction analysis in pre-pubertal and adult sheep donors. The results showed that the rates of maturation and cleavage of oocytes as well as pregnancy and lambing rates from the transfer of 2-cell embryos collected from lambs were less than those from adults (P<0.05). The global DNA methylation and hydroxymethylation and relative abundance of Dnmt1, Dnmt3a, and Tet3 mRNA were less at all stages of oocytes, zygotes, and two-cell embryos from lambs compared with those from adults (P<0.05) with no difference in relative abundance of Dnmt3b mRNA. Thus, younger donor age was associated with disturbed DNA methylation processes due to insufficient methyltransferases during gametogenesis and early embryonic development, and this may be responsible for the lesser developmental potential of oocytes and early developing embryos when oocytes are collected from lambs.

Effects of alkyl polyglycoside, a nonionic surfactant, and forage-to-concentrate ratio on rumen fermentation, amino acid composition of rumen content, bacteria and plasma in goats.

In the present study, the effects of different forage-to-concentrate ratios (F:C) and an alkyl polyglycoside (APG) supplementation on parameters of rumen and blood metabolism were investigated in goats. A 2 × 2 factorial experiment was arranged within a 4 × 4 Latin square design (four 22-day periods), using four wether goats equipped with permanent ruminal cannulas. The experimental diets included two F:C levels (40:60 vs. 60:40), and two APG supplementation levels (None or 13 ml APG daily per animal). Rumen contents and blood samples were collected at the end of each period. Dietary F:C alteration affected plasma urea and influenced the proportions of leucine, histidine, arginine, glycine, proline, alanine, valine, phenylalanine, cysteine and tyrosine in rumen content, and the proportions of methionine, threonine and proline in solid-associated bacteria (SAB) significantly. Dietary APG decreased the proportions of valine and phenylalanine in rumen content, and the histidine content of liquid-associated bacteria. The interaction between dietary F:C and APG was significant for the proportions of glycine and alanine in rumen content, and the proportions of lysine and threonine in SAB. The proportion of lysine was greater, but the proportion of threonine was less in SAB for goats fed high F:C diet without APG supplementation. The proportions of plasma free amino acids and glucose concentration were not affected by experimental treatments. These results indicated that dietary APG addition affected the amino acid composition of the rumen content and ruminal bacteria, but this depended on the dietary F:C ratio. It is necessary to validate the effectiveness of dietary APG supplementation in further studies with more animals.

Rhubarb Supplementation Promotes Intestinal Mucosal Innate Immune Homeostasis through Modulating Intestinal Epithelial Microbiota in Goat Kids

The abuse and misuse of antibiotics in livestock production pose a potential health risk globally. Rhubarb can serve as a potential alternative to antibiotics, and several studies have looked into its anticancer, antitumor, and anti-inflammatory properties. The aim of this study was to test the effects of rhubarb supplementation to the diet of young ruminants on innate immune function and epithelial microbiota in the small intestine. Goat kids were fed with a control diet supplemented with or without rhubarb (1.25% DM) and were slaughtered at days 50 and 60 of age. Results showed that the supplementation of rhubarb increased ileal villus height (P = 0.036), increased jejujal and ileal anti-inflammatory IL-10 production (P < 0.05), increased jejunal and ileal Claudin-1 expression at both mRNA and protein levels (P < 0.05), and decreased ileal pro-inflammatory IL-1β production (P < 0.05). These changes in innate immune function were accompanied by shifts in ileal epithelial bacterial ecosystem in favor of Blautia, Clostridium, Lactobacillus, and Pseudomonas, and with a decline in the relative abundance of Staphylococcus (P < 0.001) when rhubarb was supplemented. Additionally, age also affected (P < 0.05) crypt depth, cytokine production, Claudin-1 expression and relative abundances of specific genera in epithelial bacteria. Collectively, the supplementation of rhubarb could enhance host mucosal innate immune homeostasis by modulating intestinal epithelial microbiota during the early stages of animal development.