Postnatal differential expression of chemoreceptors of free fatty acids along the gastrointestinal tract of supplemental feeding v. grazing kid goats.

The gastrointestinal tract (GIT) of animals is capable of sensing various kinds of nutrients via G-protein coupled receptor-mediated signaling transduction pathways, and the process is known as 'gut nutrient chemosensing'. GPR40, GPR41, GPR43 and GPR119 are chemoreceptors for free fatty acids (FFAs) and lipid derivatives, but they are not well studied in small ruminants. The objective of this study is to determine the expression of GPR40, GPR41, GPR43 and GPR119 along the GIT of kid goats under supplemental feeding (S) v. grazing (G) during early development. In total, 44 kid goats (initial weight 1.35±0.12 kg) were slaughtered for sampling (rumen, abomasum, duodenum, jejunum, ileum, cecum, colon and rectum) between days 0 and 70. The expression of GPR41 and GPR43 were measured at both mRNA and protein levels, whereas GPR40 and GPR119 were assayed at protein level only. The effects of age and feeding system on their expression were variable depending upon GIT segments, chemoreceptors and expression level (mRNA or protein), and sometimes feeding system × age interactions (P0.05) on GPR43 expression; and there were no feeding system×age interactions (P>0.05) on GPR41 and GPR43 protein expression. The expression of GPR41 and GPR43 in rumen and abomasum linearly (P<0.01) increased with increasing age (from days 0 to 70). Meanwhile, age was the main factor affecting GPR40 expression throughout the GIT. These outcomes indicate that age and feeding system are the two factors affecting chemoreceptors for FFAs and lipid derivatives expression in the GIT of kids goats, and S enhanced the expression of chemoreceptors for FFAs, whereas G gave rise to greater expression of chemoreceptors for lipid derivatives. Our results suggest that enhanced expression of chemoreceptors for FFAs might be one of the benefits of early supplemental feeding offered to young ruminants during early development.

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 dietary supplementation with alkyl polyglycoside, a nonionic surfactant, on nutrient digestion and ruminal fermentation in goats.

The effects of dietary alkyl polyglycoside [APG, a nonionic surfactant (NIS), derived from a reaction of corn starch glucose and a natural fatty alcohol] inclusion on digestion of nutrients and ruminal fermentation in goats were examined in a 4 × 4 Latin square design using 4 ruminally and duodenally cannulated wethers (mean BW: 19.5 ± 0.8 kg). The animals were assigned to 4 dietary treatments of APG supplementation at 0, 3, 6, and 12 g/kg of DM diets and were designated as control, APG3, APG6, and APG12, respectively. The results showed that dietary APG inclusion tended to increase the intestinal digestibility of OM (linear, P = 0.09) and NDF (linear, P = 0.1), and quadratically increased (P ≤ 0.02) total tract digestibility of OM and NDF, the duodenal microbial N flow, and efficiency of microbial protein synthesis. The true ruminal digestibility and apparent total tract digestibility of N quadratically increased (P < 0.01) with increasing dietary APG. The ruminal pH values were not affected by dietary APG inclusion (P > 0.05), but the concentration of NH(3)-N (P < 0.01) and total VFA (linear and quadratic, P < 0.01) increased in the rumen fluid. Dietary APG inclusion also increased the activities of ruminal carboxymethyl cellulase (quadratic, P < 0.01) and xylanase (linear and quadratic, P < 0.01). It is concluded that APG is a potential feed additive that can be used in ruminant production; 6 g/kg in the total mixed rations for goats is recommended. It is necessary to validate the effectiveness of dietary APG inclusion in ruminant diets with more animals in further studies.

Effects of variety, sowing season and maturity stage on ruminal phosphorus release from whole maize stover and its morphological fractions.

An in situ degradation technique was used to investigate the effects of variety, season and maturity stage on ruminal Phosphorus (P) release from whole maize stover and morphological fractions from five varieties of maize (conventional maize, CM; sweet maize, SM; waxy maize, WM; high oil maize, HOM; and fodder maize, FM). Maize plants were harvested in 2005, 17 and 31 days after tasselling and manually separated into leaf blade, leaf sheath, stem and husk. Results showed that the values of rapidly released P fractions (a), slowly released P fractions (b), rate constant of P release for fraction b (c) and effective disappearance (ED) of P were significantly influenced by variety, sowing season and maturity stage (p < 0.05). The ED of P in whole maize stover among the varieties decreased in the following order: FM (89.8%) > HOM (87.9%) > CM (87.0%) > SM (86.9%) > WM (83.9%). Advanced maturity stage increased (p < 0.001) the a and ED values of P in the leaf blade and leaf sheath, but decreased (p < 0.001) these parameters in the husk. The a fraction and ED of P were higher (p < 0.001) for maize sown in spring than those sown in summer. Significant (p < 0.05) interactions among variety, sowing season and maturity stage were noted in the a and ED values of P. Effective disappearance of morphological fraction varied significantly (p < 0.001) and followed the order: stem (90.3%) > leaf sheath (88.2%) > leaf blade (85.2%) > husk (84.9%). In conclusion, most of P in maize stover could be released in the rumen. The potential pollution resulting from P excretion in faeces may be alleviated, when maize stover is largely used as the main forage source of ruminants.

The effect of dietary methionine levels on endogenous nitrogen and endogenous amino acids flows in growing goats.

The effect of dietary methionine (Met) levels on endogenous N and amino acids (AA) flows at different part of the digestive tract of growing goats was determined using a (15)N isotope dilution technique. Three goats (25 ± 2.5 kg) were fitted with the ruminal, duodenal and ileal cannulae and allocated to three dietary treatments in a 3 × 3 Latin square design. The dietary treatments consisted of a total mixed ration containing three levels of Met (0.15%, 0.25% and 0.35%) respectively. It was found that at 0.15% Met level, the lowest flow in endogenous N and total AA at the duodenum and ileum occurred. The endogenous N secretion contributed to 26% and 23% of the duodenal and ileal total N flows, respectively, and the proportions were not affected by the dietary Met levels. The duodenal and ileal flows of endogenous total AA were 11.1, 11.8, 11.3 g/d and 2.9, 3.9, 4.1 g/d respectively. The average real digestibility of N was 65%, 87% and 95% in the forestomach, intestine and whole digestive tract respectively.

Effects of yeast culture and fibrolytic enzyme supplementation on in vitro fermentation characteristics of low-quality cereal straws.

The effects of yeast culture and fibrolytic enzyme preparation (containing cellulase and xylanase) on in vitro fermentation characteristics of rice straw, wheat straw, maize stover, and maize stover silage were examined using an in vitro gas production technique. Four levels of yeast culture and fibrolytic enzyme supplements (0, 2.5, 5.0, and 7.5 g/kg of straw DM, respectively) were tested in a 4 x 4 factorial arrangement. Supplementation of yeast culture increased the cumulative gas production, theoretical maximum of gas production, rate of gas production, IVDMD, and in vitro OM disappearance (IVOMD), and decreased the lag time for each type of straw. Fibrolytic enzyme supplementation tended to increase cumulative gas production, theoretical maximum of gas production, and rate of gas production; prolonged lag time of gas production; and enhanced IVDMD and IVOMD for 4 types of cereal straws, with the significance of this effect being dependent on the level of supplemented enzymes. There were significant interactions between fibrolytic enzymes and yeast on all in vitro gas production parameters, IVDMD, and IVOMD of each type of straw. The outcome of this research indicated that the application of fibrolytic enzyme preparation and yeast culture could improve in vitro gas production fermentation of cereal straws.

["Bu-yang huanwu tang" inhibited the pathogentic process of atherosclerosis induced by cholesterol-rich diet in rabbits].

BACKGROUND AND OBJECTIVE: "Bu-yang huanwu tang", a decoction of Chinese herbs widely used in the treatment for cardio- and cerebro-vascular diseases, has been demonstrated to be able to inhibit platelet adhesion and aggregation, to lower blood lipids, to regulate vascular tone from animal experiments. The aim of this study is to determine whether this decoction inhibits the pathogentic process of atherosclerosis induced by cholesterol-rich diet in rabbits. METHODS: Three groups of rabbits received the following different diets for 9 weeks: 1. standard diet; 2. atherogenic diet(standard diet plus 1% cholesterol and 3.3% fat); 3. atherogenic diet plus this decoction(5 g.kg-1.d-1). Plasma lipids, 6-keto-PGF1 alpha, endothelin levels were detected and the histological atherosclerotic changes were evaluated. RESULTS: This decoction inhibited the progression of aortic and abdominal aortic intimal plaques and reduced aortic intimal thickening. CONCLUSION: The anti-atherogenic mechanism might be related to the decrease of plasma cholesterol and triglycerides and the increase of PGI2. The facts suggest that "Bu-yang huanwu tang" has antiatherogenic and antithrombotic effects.