H.X. Sun

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.

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 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.

Rumen methane output and fermentation characteristics of gramineous forage and leguminous forage at differing harvest dates determined using an in vitro gas production technique

Abstract An in vitro rumen gas production technique was employed to determine the methane production and fermentation characteristics of Leymus chinensis and Medicago ruthenica at differing harvest dates (May 15, May 30, June 30, July 30, August 30 and September 30), which are sequential phases within a single continuous growth of two 10-year-old pastures. To quantify the rate of degradation and compare in vitro rumen fermentation characteristic, a logistic-exponential model, where initial gas volume was zero (LE0), was used to fit gas production and methane output results. Dried, milled forage samples were incubated in vitro for 72 h at 39°C and gas production was recorded intermittently throughout the incubation and gas samples were collected to measure methane production. Results showed that there were significant interactions between species and harvest for all chemical composition variables (P