Effects of grain type and conditioning temperature during pelleting on growth performance, ruminal fermentation, meat quality and blood metabolites of fattening lambs.

Ruminants can tolerate moderate concentrations of dietary tannin, making it feasible to replace corn with sorghum in ruminant diets; however, conditioning temperature of pelleted total mixed ration (PTMR) greatly affects nutrient digestibility. The objective was to determine effects of grain type and conditioning temperature during pelleting on growth performance, ruminal fermentation, meat quality and blood metabolites of fattening lambs. This was a 2 × 3 factorial study, with corn and sorghum and three conditioning temperatures (65, 75 and 85 °C) in a randomized complete design, with 36 lambs (120 ±â€¯10.2 d and 24.9 ±â€¯3.3 kg) grouped by weight and randomly allocated. The resulting six PTMRs were referred to as 65-S, 75-S and 85-S for sorghum-based diets, and 65-C, 75-C and 85-C for corn-based diets, for low, medium and high pelleting temperatures, respectively. There was no grain type × conditioning temperature (Grain × Temp) interaction on growth performance and apparent nutrient digestibility. Furthermore, grain type did not affect DM intake (DMI), average daily gain (ADG) or feed conversion ratio (FCR) of fattening lambs. Pelleting at 75 °C improved ADG (P < 0.03) and FCR (P < 0.02) of fattening lambs compared to other temperatures. There was a Grain × Temp interaction (P < 0.01) on ruminal pH (lowest in lambs fed 75-S). There tended (P = 0.07) to be a Grain × Temp interaction for total volatile fatty acid (VFA), and there were Grain × Temp interactions for molar proportions of acetate (P < 0.04), butyrate (P < 0.03) and branch-chained VFA (P < 0.01). Lambs fed sorghum-based PTMR had greater molar proportion of propionate (P < 0.03) and lower acetate to propionate ratio (A:P, P < 0.04). Lambs fed sorghum-based PTMR had higher plasma concentrations of urea nitrogen (N) (P < 0.03), glucose (P < 0.01) and alkaline phosphatase (P < 0.05), whereas other blood metabolites were not affected by treatments. There were Grain × Temp (P < 0.03) interactions for color coordinates of longissimus and mid-gluteal muscle. Lambs fed sorghum-based PTMR had lower (P < 0.01) dressing percentage and meat quality than those fed corn-based PTMR. We concluded that sorghum can replace corn in lamb diets without compromising growth performance and feed efficiency; furthermore, feeding sorghum vs corn improved rumen fermentation, with reduced A:P ratio and enhanced N and glucose utilization. Finally, pelleting at 75 °C increased feeding value of either sorghum- or corn-based PTMR for fattening lambs.

Effects of different sources of protein on the growth performance, blood chemistry and polypeptide profiles in the gastrointestinal tract digesta of newly weaned piglets.

To determine the effects of different sources of protein on the growth performance of newly weaned piglets, 72 newly weaned piglets were randomly assigned to three groups fed different diets (soya bean, casein and dried distillers' grain with solubles (DDGS) feeds). Casein and DDGS feeds consisted of soya bean feed in which 5% of the CP was replaced with casein- or DDGS-derived CP respectively. Blood and chyme samples were collected from each piglet 2 h post-feeding on days 0 and 28 of the feeding period. The DDGS feed decreased DMI (p = 0.024) and increased FCR (p = 0.025) due to lower nitrogen utilization (p = 0.078) than those of other feeds. Total amino acid content in chyme demonstrated that casein feed digested rapidly in the duodenum (p = 0.005), whereas DDGS feed was digested primarily in the distal jejunum (p = 0.003) and ileocecum (p = 0.002). However, polypeptide profiles in chyme exhibited a pattern different from those of amino acids. There were no differences in the polypeptide profiles in the stomachs of piglets fed soya bean or casein feeds (p > 0.05), but soya bean group had greater amounts of small polypeptides (mass under m/z 3000 Da) in the duodenum (p = 0.052) than other groups. In contrast, the DDGS feed group had more large polypeptides (m/z 3000-4000 Da) in the stomach than the other groups (p < 0.001). In addition, 10 pairs of polypeptides with matching masses were identified in the plasma and digesta, indicating that polypeptides may have been transported across the intestinal epithelial cells and into the blood. Taken together, substitution of 5% of the CP in soya bean meal-based feed with DDGS-derived CP decreased the growth performance of newly weaned piglets due to poor digestibility and N utilization of DDGS feed, as well as untimely digestion of casein feed.

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 lg/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 lg/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)-c, interleukin (IL)-2, IL-4 and IL-10 were increased by WHA stimulation without tannic acid. However, the increased effects on IFN-c 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.

Effect of tea catechins on regulation of cell proliferation and antioxidant enzyme expression in H2 O2 -induced primary hepatocytes of goat in vitro.

Tea catechins (TC) are polyphenols that have potent antioxidant activity. The objectives of this study were to determine the effects of TC on antioxidant status of hepatocytes challenged with H2 O2 . Primary hepatocytes of goat were exposed to 1 mm H2 O2 without or with 5, 50 and 500 µg/ml TC. The cells were harvested at 48 h post-treatment to determine effects of TC on proliferation, apoptotic features and membrane integrity of cells, and expression of genes and activities of antioxidant enzymes. H2 O2 exposure caused damage to cells (p < 0.001). A lower concentration of TC (5 µg/ml) displayed a protective effect by inhibiting exorbitant cell proliferation and DNA degradation. Both H2 O2 exposure and TC pre-incubation affected expression of antioxidant enzymes at mRNA and protein levels (p < 0.001). The activities of catalase (CAT) (p = 0.027), CuZn-superoxide dismutase (CuZn-SOD) (p < 0.001) and glutathione peroxidase (GPx) (p < 0.001) increased with TC pre-incubation followed by H2 O2 challenge. Changes of CuZn-SOD activity induced by H2 O2 and TC basically paralleled the changes in the corresponding mRNA and protein levels, but the correlation in CAT and GPx expression displayed slightly different patterns at different concentrations of TC. These findings infer that oxidative stress can induce deleterious cellular responses and this unfavourable condition may be alleviated by treatment with TC.

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.

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.

Dietary inclusion of tea catechins changes fatty acid composition of muscle in goats.

This study was conducted to examine dietary tea catechins (TC) supplementation on the fatty acid composition of muscle and ruminal bacteria in goats fed a maize stover-based diet. Forty goats, 8 months old (16.2 ± 1.2 kg), were randomly divided into four equal groups (10 animals in each group) and assigned to four experiment diets with TC supplementation at four levels (0, 2,000, 3,000 and 4,000 mg TC/kg feed, namely TC0, TC2000, TC3000 and TC4000, respectively). After a 60-day feeding period, all the goats were slaughtered and sampled. The results showed that dietary TC inclusion increased the average daily gain (ADG), protein content in the semimembranosus muscle and dry matter in the longissimus dorsi muscle (LD). Dietary TC supplementation increased the ratio of n-6 to n-3 fatty acid, the ratio of polyunsaturated fatty acids to saturated fatty acids was higher in TC3000 and TC4000 than in TC0 and TC2000 for LD. The current results implied that dietary inclusion of a suitable TC dose could improve the growth performance and increase the proportions of unsaturated fatty acids in muscle, and the biohydrogenation of ruminal microorganisms might change the profiles of fatty acids in the muscle of growing goats.

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.

Monoclonal antibody against CD45RB for the therapy of rejection and autoimmune diseases.

Rejection continues to be the single largest impediment to successful organ transplantation. Current therapy, which must be taken for a lifetime is nonspecific and has significant side effects including infection and cancer. There is a need to develop improved means of immunosuppression. The current goal of transplantation immunology is to induce a prolonged state of nonreactivity to the allograft but preserving an otherwise intact immune system (tolerance). We have recently reported that a monoclonal antibody against CD45RB is a potent immunosuppressive agent, and that it induces donor specific tolerance in the mouse. In this contribution we briefly review our understanding of the molecular basis for the activity of this therapy and update results in various transplant and autoimmune disease animal models. The clinical relevance and future development of this novel therapy is also discussed.

Prevention and reversal of renal allograft rejection by antibody against CD45RB.

Rejection continues to be the single largest impediment to successful organ transplantation. Antilymphocyte globulin, which contains antibodies that react with the leukocyte common antigen known as CD45, has proved to be one of the most effective agents for preventing rejection. We have shown earlier that a monoclonal antibody directed against the RB isoform of CD45 substantially inhibits the alloreactivity of human CD4+ lymphocytes in vitro. Here we investigate whether CD45RB could be an appropriate target for preventing renal allograft rejection in mice. Mice treated with two injections of a monoclonal antibody (MB23G2) raised against CD45RB protein all survived and had normal renal function. Furthermore, this antibody reversed acute rejection when therapy was delayed until day 4, and the mice survived for their natural lifespan. The immunosuppression achieved may find application in the prevention and treatment of transplant rejection in man.

Altered gene expression of cytokine, ICAM-1, and class II molecules precedes mouse intestinal allograft rejection.

Rapid and severe rejection remains a major obstacle to successful clinical intestinal transplantation (IT). The aggressive nature of rejection in IT has been attributed to the increased massive immune stimulus provided by large numbers of resident lymphocytes, antigen presentation capacity of enterocytes, and graft damage mediated by luminal microflora. Early small bowel expression of proinflammatory cytokines, MHC class II, and adhesion molecules may also promote IT rejection, but the lack of a mouse model has hampered extensive studies of gene expression in IT. Using a recently developed surgical model, we examined the temporal pattern of gene expression in CB6F1 (H-2b/d) vascularized, heterotopic intestinal allografts transplanted into BALB/c (H-2d) mice. Although histological evidence of rejection was not present until day 7 in allografts, Northern blot analysis demonstrated increases in TNF alpha gene transcripts as early as day 3, followed by the expression of IL-1 beta, intercellular adhesion molecule-1, and MHC class II by day 5. Using reverse-transcriptase polymerase chain reaction, IFN-gamma was detected in allografts by day 3 and persisted to day 10. In contrast, IL-2, IL-4, IL-5, and IL-6 mRNA transcripts peaked by day 5 and then decreased, suggesting that both Th1 and Th2 subsets are involved in the rejection of unmodified small bowel allografts. The early and progressive expression of TNF alpha and IL-1 beta as well as IFN-gamma, intercellular adhesion molecule-1, and MHC class II in IT rejection may contribute to the difficulty in controlling IT rejection with present immunosuppression.

Treatment with FK506 prevents rejection of rat colon allografts.

Colon transplantation has been proposed as a method to improve the function of an intestinal allograft. The present study examined the risk of colon rejection and the effect of FK506 on colon rejection in BN-->LEW rats with orthotopic bowel transplants. The first 4 groups included rats with untreated allografts (group 1), rats with isografts treated with 0.6 mg/kg FK506 (group 2), rats with allografts treated with 0.6 mg/kg FK506 (group 3), and rats with allografts treated with 0.4 mg/kg FK506 (group 4). In each of these groups (10-12 rats), half of the animals received a small bowel graft only (SB), while the other half received a small bowel, ascending colon, and cecum graft (SBC). The animals were followed daily until they died or were killed at 4 weeks. In group 5, an additional 18 untreated rats with SBC allografts were randomly killed on the third, fifth, seventh, and tenth postoperative days to study the sequential histopathologic and immunopathologic changes of colon rejection. There was no difference in survival, body weight, nutritional parameters, or bacterial contamination after SB and SBC transplantation. Intestinal transit was slower after SBC than SB transplantation (P < 0.05). Sequential histopathologic studies revealed that (1) the severity and time course of colon rejection was similar to small intestine rejection, and (2) the features of colon rejection were similar to ulcerative colitis. There was no evidence of graft-versus-host disease after SBC transplantation. In summary, adding a segment of large bowel to a small bowel allograft does not increase the risk of rejection or surgical complications. The transplanted colon slows intestinal transit. Treatment with FK506 effectively prevents colon rejection. These data suggest that adding a colon graft may improve the outcome of clinical small bowel transplantation.

Transplantation of segmental rat intestinal grafts including the ileocecal value and the ascending colon.

Extrinsic denervation and lymphatic disruption impair nutrient absorption after small bowel transplantation. The present study was undertaken to determine whether adding the ileocecal valve with or without the ascending colon would improve the function of a segmental intestinal graft. Five groups of Lewis rats (n = 10/group) were studied. Group I had a sham laparotomy. Groups II, III, IV, and V had the native jejunum, ileum, and cecum replaced with a graft. Inbred Lewis rats were used as isogeneic donors for the transplants to avoid the confounding effect of graft rejection. Group II had the entire jejunum and ileum transplanted. Group III had 20 cm of terminal ileum transplanted. Group IV had 20 cm of the terminal ileum including the ileocecal valve transplanted. Group V had 20 cm of the terminal ileum, the ileocecal valve, and the ascending colon transplanted. The terminal ileum-transplanted and terminal ileum/ileocecal valve-transplanted groups lost more than 25% of their preoperative weight by the end of the second postoperative week; most of these animals were killed because of inanition. In contrast, the sham laparotomy, jejunum/ileum-transplanted, and ascending colon-transplanted groups remained healthy until completion of the study on the 28th postoperative day. The ascending colon-transplanted group had slower intestinal transit and less bacterial contamination of the terminal ileum compared with the terminal ileum-transplanted and terminal ileum/ileocecal valve-transplanted groups (P < 0.05). Transplantation of the ascending colon and the ileocecal valve significantly improves the function of segmental small bowel isografts in rats. These data suggest that adding a colonic segment may be a simple method to improve the function of short-segment cadaveric and living-related intestinal grafts in humans.