No abstract

A rapid lateral flow immunoassay screening method has been developed for the determination of sulfamonomethoxine (SMM) residues in swine urine. For this purpose, a specific monoclonal antibody (mAb), SMM4B9 for SMM, was generated and characterized. The mAb showed low cross-reactivity (not larger than 0.3%) to other sulfonamides and other potentially occurring analytes. Based on the competitive immunoassay principle, the strip was developed with the mAb SMM4B9 and applied to the screening of SMM residues. The test strip is made up of a sample pad, a gold-conjugate SMM4B9 reagent pad, a blotted test membrane containing a test line, a control line (a nitrocellulose membrane spotted with SMM-BSA and goat anti-mouse antibody, respectively), and an absorbent pad. The test could be accomplished within 8-10 min. It was shown that the sensitivity of the test strip was as low as 5 ng ml(-1) of SMM and the half of maximal inhibition concentration (IC50) was calculated to be 10.78 +/- 0.22 ng ml(-1) by relative optical density. In unaided visual assessment the detection limit of the strip was 15 ng ml(-1). For samples spiked at 20 and 30 ng ml(-1) the coefficient of variation (CV (%)) was between 2.3 and 7.1%. When the test strip was compared with high-performance liquid chromatography (HPLC) analysis for naturally contaminated swine urine samples, the difference in results was less than 6.1%. The data suggest that the method has advantages of high sensitivity, specificity, simplicity and speed of performance, as well as the characteristics of repeatability, reproducibility or accuracy and assurance. Therefore, the test strip is suitable to determine SMM residues in swine urine rapidly and reliably by quantitative, semi-quantitative or qualitative detection.

The present aim was to investigate the effects of traditional Chinese medicine prescriptions (TCM) on body temperature, blood physiological parameters, nutrient apparent digestibility and growth performance of beef cattle under heat stress conditions. Twenty-seven beef cattle were randomly divided into three groups as following; i) high temperature control (HTC), ii) traditional Chinese medicine prescriptions I+high temperature (TCM I) and iii) traditional Chinese medicine prescriptions II+high temperature (TCM II) (n = 9 per group). The results showed that the mean body temperature declined in TCM II treatment (p<0.05). Serum T3 and T4 levels with TCM I and TCM II treatments elevated (p<0.05), and serum cortisol levels of TCM I treatments decreased (p<0.05), compared with the HTC group. Total protein, albumin, globulin in TCM II treatments elevated and blood urea nitrogen levels of both TCM treatments increased, but glucose levels of both TCM treatments decreased, compared with the HTC group (p<0.05). The apparent digestibility of organic matter and crude protein with TCM I treatment increased, and the apparent digestibility of acid detergent fiber elevated in both TCM treatments (p<0.05). Average daily feed intake was not different among three groups, however average daily gain increased and the feed:gain ratio decreased with both TCM treatments, compared with the HTC group (p<0.05). The present results suggest that dietary supplementation with TCM I or TCM II improves growth performance of heat stressed beef cattle by relieving heat stress responses and increasing nutrient apparent digestibility.

This study aims to investigate the effects of probiotics and Chinese medicine polysaccharides (CMPs) on growth performance, blood indices, rumen fermentation, and bacteria composition in lambs. Forty female lambs were randomly divided into four groups as follows: control, probiotics, CMP, and compound (probiotics + CMP) groups. The results showed that probiotics treatment increased the concentrations of blood glucose (GLU) and immunoglobulin G (IgG) and enhanced rumen microbial protein contents but declined the value of pH in rumen fluid compared with the control (P &lt; 0.05). Furthermore, supplementation with CMP enhanced the average daily gain (ADG) and the contents of IgA, IgG, and IgM in the serum but decreased the F:G ratio compared with the control (P &lt; 0.05). Besides, both CMP and compound (probiotics + CMP) treatments decreased the ratio of acetic acid and propionic acid compared with the control (P &lt; 0.05). High-throughput sequencing data showed that at the genus level, the relative abundance of Veillonellaceae_UCG-001 in the probiotics group was increased, the relative abundance of Succiniclasticum and norank_f__Muribaculaceae in the CMP group were enhanced, and the relative abundance of Ruminococcaceae_UCG-002 in the compound group was raised compared with the control (P &lt; 0.05). In summary, supplementation with probiotics can promote rumen protein fermentation but decrease the diversity of bacteria in rumen fluid; however, CMP treatment increased the relative abundance of Fibrobacteria, changed rumen microbial fermentation mode, increased the immune function, and ultimately improved the growth performance.

An experiment was conducted to determine the effects of soy isoflavone daidzein on carcass characteristics, fat deposition, meat quality, and blood metabolites in finishing steers. Fourteen crossbred steers were used in a 120-d finishing study. These steers were stratified by weight into groups and randomly allotted by group to one of two dietary treatments: (1) control and (2) daidzein (500 mg/kg concentrate). The steers were fed a 90% concentrate diet. Supplemental daidzein did not affect slaughter weight, hot carcass weight, and dressing percentage, but tended to reduce fat proportion (not including intramuscular fat) in carcass and backfat thickness of steers. The carcass bone proportion was greater in steers fed daidzein diets than those fed control diets. Daidzein supplementation reduced pH at 24 h after slaughtered and moisture content and increased isocitrate dehydrogenase activity, fat content (16.28% and 7.94%), marbling score (5.29 and 3.36), redness (a*), and chroma (C*) values in longissimus muscle relative to control treatment. The concentrations of blood metabolites including glucose, blood urea nitrogen, triglyceride, total cholesterol, non-esterified fatty acid, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were all lower in steers fed daidzein diets than those fed control diets. Current results suggest that supplemental daidzein can affect lipid metabolism, increase intramuscular fat content and marbling score, and improve meat quality in finishing steers. Daidzein should be a promising feed additive for production of high-quality beef meat.