Survival of Listeria monocytogenes in cheese made of unpasteurized goat milk

Food-born infections with Listeria monocytogenes have been reported during recent years, cheese being mentioned as one of the foods responsible. A classical opinion is that cheese represents a very inhospitable environment for pathogens due to antagonism by the starter culture of lactic-acid-producing organisms. In order to study the survival of L. monocytogenes in goat cheese, cheeses were made with the addition of L. monocytogenes cultures. The maximum survival time for L. monocytogenes was 18 weeks in two of the cheeses. It is concluded that L. monocytogenes has the ability to survive in semi-soft cheese made of unpasteurized goat milk during normal curing (2–3 months).     

Survival and colonization of orally administered Lactobacillus plantarum 301102 in porcine gastrointestinal tract

The purpose of this study was to evaluate the survival and colonization of Lactobacillus plantarum 301102 in porcine gastrointestinal tract and its influence on the intestinal microflora. This strain was isolated from traditional cheese from Inner Mongolia, China. Fermented milk prepared with strain 301102 was administered to pigs and fecal microflora was examined. Intestinal passage of strain 301102 was monitored by a combination of selection with selective medium and the carbohydrate fermentation test, and confirmed by analysis of plasmid DNA patterns. Colonization of this strain was assessed by recovery 7 days after administration. The numbers of Lactobacillus and Bifidobacterium cells in the feces of pigs administered fermented milk prepared with strain 301102 were increased. This strain was recovered from all the pigs during the administration period, and from four of six pigs 7 days after administration. L. plantarum 301102 can pass through the gastrointestinal tract, balance the intestinal microflora, and colonize the intestinal tract, and is therefore an appropriate candidate for a probiotic.     

Physicochemical and sensory characteristics of yoghurts made from goat and cow milk

Substituting goats' milk for cows' milk could improve the quality of dairy products, because it adds new sensorial characteristics. The aim of this study was to develop a type of yoghurt using goats' milk (25, 50, 75 and 100%) in place of cows' milk and to compare their characteristics. Physicochemical, microbiological and sensory characteristics were evaluated using a nine‐point hedonic scale and purchase intention test. The data obtained in the physicochemical analysis were submitted to regression analysis and the sensory results were evaluated through analysis of variance. Among the physicochemical characteristics of the yoghurts, variation (P < 0.05) of ash, acidity and lactose was observed. Tasters in the sensory analysis indicated that yoghurts up to 50% of goats' milk received favorable averages; with lower scores for higher goats' milk concentrations (75% and 100%). No difference was reported in acidity. Replacing cows' milk with goats' milk in yoghurt preparation promotes variations in the physicochemical characteristics for ash, acidity and lactose. However, it does not cause alterations in the sensory attributes (50% goat milk) and therefore could be considered as an alternative for the production of dairy products. © 2016 Japanese Society of Animal Science     

Selection and characterization of broad‐spectrum antibacterial substance‐producing Lactobacillus curvatus PA40 as a potential probiotic for feed additives

Lactic acid bacteria were screened for potential probiotics for use as feed additives. We obtained 3,000 isolates from feces of: cattle, dogs, goats, and infants; milk; yogurt; cheese; fermented sausages; Kimchi; and Cheonggukjang and tested their antibacterial activity toward indicator pathogens, including Bacillus cereus, Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella enterica Enteritidis. We further tested their tolerance to artificial gastric juice (1% [w/v] pepsin, pH 2.5) and bile acid (0.1% [w/v] oxgall, pH 6.8). Six isolates exhibited strong antibacterial activity against indicator pathogens. The PA40 isolate from Kimchi exhibited marked resistance to artificial gastric juice and bile acid. The antibacterial substances produced by PA40 were stable to heat, pH, and enzymes. Strain PA40 was identified as a Lactobacillus curvatus strain using chemical tests and 16S rDNA sequencing and produced 248.4 mmol/L lactic acid after 48 hr of fermentative growth. The L. curvatus PA40 strain was also highly tolerant of the artificial gastrointestinal model system. Our results indicate that L. curvatus PA40 could be used as a potential probiotic feed additive.     

Effect of short‐chain fatty acids on triacylglycerol accumulation,lipid droplet formation and lipogenic gene expression in goat mammary epithelial cells

Short‐chain fatty acids (SCFAs) are the major energy sources for ruminants and are known to regulate various physiological functions in other species. However, their roles in ruminant milk fat metabolism are still unclear. In this study, goat mammary gland epithelial cells (GMECs) were treated with 3 mmol/L acetate, propionate or butyrate for 24 h to assess their effects on lipogenesis. Data revealed that the content of triacylglycerol (TAG) and lipid droplet formation were significantly stimulated by propionate and butyrate. The expression of FABP3, SCD1, PPARG, SREBP1, DGAT1, AGPAT6 and ADRP were upregulated by propionate and butyrate treatment. In contrast, the messenger RNA (mRNA) expression of FASN and LXRα was not affected by propionate, but reduced by butyrate. Acetate had no obvious effect on the content of TAG and lipid droplets but increased the mRNA expression of SCD1 and FABP3 in GMECs. Additionally, it was observed that propionate significantly increased the relative content of mono‐unsaturated fatty acids (C18:1 and C16:1) at the expense of decreased saturated fatty acids (C16:0 and C18:0). Butyrate and acetate had no significant effect on fatty acid composition. Overall, the results from this work help enhance our understanding of the regulatory role of SCFAs on goat mammary cell lipid metabolism.     

Enhancement of viability of a probiotic Lactobacillus strain for poultry during freeze‐drying and storage using the response surface methodology

A rotatable central composite design (CCD) was used to study the effect of cryoprotectants (skim milk, sucrose and lactose) on the survival rate of a probiotic Lactobacillus strain, L. reuteri C10, for poultry, during freeze‐drying and storage. Using response surface methodology, a quadratic polynomial equation was obtained for response value by multiple regression analyses: Y = 8.59546 ? 0.01038 X₁ ? 0.09382 X₂ ? 0.07771 X₃ ? 0.054861 X₁² ? 0.04603X₃² ? 0.10938 X₁X₂. Based on the model predicted, sucrose exerted the strongest effect on the survival rate. At various combinations of cryoprotectants, the viability loss of the cells after freeze‐drying was reduced from 1.65 log colony forming units (CFU)/mL to 0.26–0.66 log CFU/mL. The estimated optimum combination for enhancing the survival rate of L. reuteri C10 was 19.5% skim milk, 1% sucrose and 9% lactose. Verification experiments confirmed the validity of the predicted model. The storage life of freeze‐dried L. reuteri C10 was markedly improved when cryoprotectants were used. At optimum combination of the cryoprotectants, the survival rates of freeze‐dried L. reuteri C10 stored at 4°C and 30°C for 6 months were 96.4% and 73.8%, respectively. Total viability loss of cells which were not protected by cryoprotectants occurred after 12 and 8 weeks of storage at 4°C and 30°C, respectively.     

Effect of a probiotic Lactobacillus plantarum TN8 strain on trinitrobenzene sulphonic acid‐induced colitis in rats

This study aimed to investigate the potential effects of an oral treatment by a newly isolated probiotic Lactobacillus plantarum TN8 strain on trinitrobenzene sulphonic acid (TNBS)‐induced colitis in Wistar rats. Thus, 18 rats were divided into three groups (n = 6 per group): group 1 (control) – rats not receiving TNBS application; group 2 – rats receiving an intrarectal TNBS infusion (100 mg/kg TNBS dissolved in ethanol); and group 3 – rats treated with intragastrical TN8 strain once per day (for 5 days before TNBS induction). The performance and the effects of the probiotic treatment were evaluated using a series of histological, biophysical and biochemical analyses. The results have shown that the treatment with the L. plantarum TN8 strain improves the body weight and reduces the diarrhoea, colonic mucosal inflammation and colon shortening. TN8‐treated rats showed a significant decrease in the total cholesterol content from 1.86 (for group 2) to 1.32 mmol/l and in triglyceride (TG) content from 2.09 (for group 2) to 1.23 mmol/l. Furthermore, the findings revealed that the high‐density lipoprotein (HDL) cholesterol contents increased from 0.95 to 1.02 mmol/l. The histological studies have confirmed that the architecture of the liver and kidney tissues of the TN8‐treated rats were found to be improved. Overall, the results suggest that the L. plantarum TN8 presents promising perspectives for the development of safe and cost‐effective agents for the prevention or alleviation of several intestinal pathologies.     

自主筛选的植物乳杆菌对酸羊乳品质与功能特性的影响

为改善酸羊乳风味与品质,提高酸羊乳的功能价值,将自浆水中筛选的植物乳杆菌JS5和JS19用于羊乳发酵,研究其对酸羊乳理化性质、质构特性及功能特性的影响。结果表明：2 种植物乳杆菌与商业发酵剂复合发酵后,均能在贮藏期内有效提高酸羊乳持水性和表观黏度,降低其硬度与胶着性,促进乙醛和双乙酰的释放;添加植物乳杆菌JS5的酸羊乳胆固醇降解率显著高于对照组（P＜0.05）,最高可达36.62%;添加植物乳杆菌JS19的酸羊乳体外抗氧化能力更强,贮藏1 d时1,1-二苯基-2-三硝基苯肼自由基清除率高达70.58%,铁离子还原/抗氧化能力达32.03 μmol/L。2 种菌株均为适用于羊乳发酵生产的优良菌株。     

D‐loop sequence mitochondrial DNA variability of Sarda goat and other goat breeds and populations reared in the Mediterranean area

To provide useful knowledge on goat breed origin and history, we studied the mitochondrial DNA (mtDNA) of 69 goats from five different breeds, Camosciata delle Alpi, Maltese, Nubian, Saanen and Sarda, and one population, the Tunisian. All goats analysed displayed a moderate haplotype and nucleotide diversity. The highest was in the Sarda – the autochthonous breed reared in Sardinia. On the basis of mtDNA control region sequences, animals showed a high genetic haplotype diversity, 35 haplotypes were each represented by a single sequence and only a few haplotypes were shared among the animals. New haplotypes of goats reared in the Mediterranean area were identified and the majority of Italian goats belonged to haplogroup A. This result confirmed worldwide distribution and diversity of haplogroup A.     

All‐trans retinoic acid improves goat oocyte nuclear maturation and reduces apoptotic cumulus cells during in vitro maturation

All‐trans retinoic acid (t‐RA) is a natural component and representative physiologically active metabolite of vitamin A, having multiple physiologic functions. The objective of this study was to evaluate the effect of t‐RA on goat oocyte maturation and cumulus cell apoptosis during in vitro maturation (IVM). Immature goat cumulus‐oocyte complexes (COCs) were matured in vitro in the absence or presence of t‐RA at concentrations of 10 nmol/L, 100 nmol/L and 1000 nmol/L. Oocyte maturation and embryo development were assessed by polar body formation and parthenogenetic activation, respectively. Oocyte survival was checked by Trypan blue staining. Apoptosis of cumulus cells was analyzed by terminal deoxynucleotidyl transferase nick end labeling staining and quantitative real‐time PCR. In comparison with the control group, 100 nmol/L and 10 nmol/L t‐RA significantly improved goat nuclear oocyte maturation and survival (P < 0.05). Addition of 1000 nmol/L t‐RA improved nuclear maturation (P < 0.05), but had no effect on survival of goat oocytes. t‐RA had no positive effect on goat parthenogenetic embryonic cleavage, blastocyst formation or total cell numbers. However, t‐RA inhibits the apoptosis of cumulus cells (P < 0.01). t‐RA treatment up‐regulated the expression of B‐cell lymphoma 2 (BCL‐2), catalase (CAT) (P < 0.05) and down‐regulated the expression of Caspase‐8 (P < 0.05). In conclusion, t‐RA has positive effects on goat oocyte nuclear maturation and reduces apoptotic cumulus cells during IVM.     

Quantitative real‐time PCR monitoring of Escherichia coli and Clostridium perfringens with oral administration of Lactobacillus plantarum strain Lq80 to weaning piglets

Levels of fecal or intestinal lactobacilli, Escherichia coli and Clostridium perfringens, and the prevalence of clostridial alpha toxin gene and heat‐stable toxin (ST) gene of enterotoxigenic E. coli (ETEC) were monitored in weaned piglets before (day 0) and during (days 7, 14, and 21) the administration of Lactobacillus plantarum strain Lq80. Lactobacilli were enumerated in a culture‐dependent method. The remainders were determined by quantitative real‐time PCR. In this quantitative real‐time PCR method, the detection limit was proved to be as low as 10³ cells/g feces or intestinal contents. Number of lactobacilli increased from day 0 to day 7 (P < 0.05), to day 14 (P < 0.05), and to day 21 (P = 0.07) in the Lq80‐administered group. L. plantarum contributed to as low as 10% of the lactobacillal population in the Lq80‐administered group. The number of E. coli and C. perfringens, and the prevalence of alpha toxin gene in feces or intestinal contents of the Lq80‐administered group decreased, at least in the first week of the postweaning period. Oral administration of L. plantarum strain Lq80 can stimulate the growth of indigenous lactobacilli and decrease ST‐producing ETEC and C. perfringens in the intestine of postweaning piglets.     

Physico‐chemical characteristics of Longissimus lumborum muscle in goats subjected to halal slaughter and anesthesia (halothane) pre‐slaughter

This study assessed the effect of halal slaughter and anesthesia pre‐slaughter followed by bleeding on meat quality characteristics of goats. Eleven male Boer cross goats were divided into two groups and subjected to either halal slaughter (HS) or anesthesia with halothane and propofol pre‐slaughter (AS). At pre‐rigor, HS had significantly lower (P < 0.05) muscle pH and glycogen than AS. However, no significant difference was observed in the pH and glycogen content between the treatments on 1, 3 and 7 days post mortem. The drip loss of HS was significantly lower (P < 0.05) than that of AS at all aging periods. Treatment had no effect on sarcomere length, myofibrillar fragmentation index and shear force values, loss of thiol groups and degradation of major myofibrillar proteins. It can be concluded that HS did not have deleterious effect on meat quality traits of goat when compared to AS.     

Partial cDNA sequence of a relaxin‐like factor (RLF) receptor,LGR8 and possible existence of the RLF ligand‐receptor system in goat testes

Relaxin‐like factor (RLF), also known as insulin‐like factor 3 (INSL3), is produced by testicular Leydig cells, but its specific receptor LGR8 (leucine‐rich repeat family of G‐protein‐coupled receptor 8) has not been identified in goats. This study aimed to identify complementary DNA (cDNA) sequences of goat LGR8, and characterize the expression of both RLF and LGR8 in goat testes by RT‐PCR and immunohistochemistry. Testes were collected from immature (3‐month‐old) and mature (24‐month‐old) Saanen goats, and partial cDNA sequences of the goat homologue of human LGR8 were identified. The sequence encoded a reduced peptide sequence of 167 amino acids, which corresponded to transmembrane regions 2 through 5, followed by the beginning of intracellular loop 3 of human LGR8. Expression of both LGR8 and RLF genes was drastically increased in mature testes compared with immature ones. Although RLF protein was restricted to Leydig cells, LGR8 protein was detected in both Leydig cells and seminiferous epithelial cells (possibly germ cells and Sertoli cells). These results reveal a possible existence of the RLF‐LGR8 ligand‐receptor system within the goat testis, suggesting that RLF may play a role in testicular function through LGR8 on Leydig cells and seminiferous epithelial cells in an autocrine and/or paracrine manner.     

Comparison of spray‐dried egg and albumen powder with conventional animal protein sources as feed ingredients in diets fed to weaned pigs

We evaluated the apparent (AID) and standardized ileal digestibility (SID) of amino acids (AA) in spray‐dried egg (SPE) and albumen powder (AP) compared with spray‐dried porcine plasma (SDPP), dried porcine solubles (DPS) and fish meal (FM). Additionally, the effects of these egg byproducts as a replacement for conventional animal proteins on the performance and nutrient digestibility of piglets were studied. In Exp. 1, six barrows fitted with ileal T‐cannulas were allotted to a 6 × 6 Latin Square design and fed six diets. The AID and SID of AA were generally higher in AP and FM (P < 0.01) than in the other protein sources. In Exp. 2, 150 piglets weaned at 21 days, were fed diets containing the five protein sources for 3 weeks. Weight gain of piglets fed SDPP was the highest among the treatments. Dry matter and protein digestibility for pigs offered SDPP were higher (P < 0.01) than those offered FM and DPS. AP decreased (P < 0.05) Escherichia coli counts in the cecum. DPS decreased (P < 0.05) serum diamine oxidase compared with SPE. In conclusion, AP and SPE are competitive with traditional animal protein sources and can be successfully fed to piglets without compromising performance.     

Influences of quorum‐quenching probiotic bacteria on the gut microbial community and immune function in weaning pigs

The aim of this study is to investigate the dynamic gut microbial diversity in weaning swine after administering feed supplemented with probiotic bacteria that specifically inhibit the activity of quorum molecules. Initially, the universal quorum molecule autoinducer‐2 (AI‐2) bioassay results indicated that AI‐2 activity was profoundly inhibited in enterohemorrhagic Escherichia coli (EHEC) O157:H7 in the presence of Lactobacillus acidophilus strain 30SC cell extract, although the growth of EHEC was not affected. Based on plate counting results, bacterial community analysis revealed a specific reduction in coliforms compared to the control, whereas the population of lactobacilli increased in weaning swine in in vivo trials. Supplementation with L. acidophilus strain 30SC did not affect the counts of other communities, such as total aerobes and yeast/mold. In addition, PCR‐denaturing gradient gel electrophoresis analysis showed a significant difference in the 16S rRNA gene products after administering L. acidophilus strain 30SC. Selected bands were sequenced, and most of them were identified as uncultured bacterium clones or a Lactobacillus‐ and Bifidobacterium‐specific community. Therefore, our results indicate that quorum‐quenching probiotic bacteria can significantly modulate the gut microbiota of swine and these beneficial effects can contribute to the improvement of performance and health in the gastrointestinal tract of weaning pigs.     

2910年国内外蜂胶研宄概况（一）

对2010年国内外蜂胶的研究概况进行了综述,对公开发表的227篇中英文文献及11篇硕士学位论文的研究领域、地域分布、刊物分布等情况进行了统计分析和评价,并重点介绍了蜂胶化学成分、药理活性、提取工艺、加工工艺、质量控制以及在农业、畜牧业等方面的研究与应用新进展。     

Effect of n‐3 PUFA‐rich fish oil supplementation during late gestation on kidding,uterine involution and resumption of follicular activity in goat

We have shown that dietary supplementation of n‐3 polyunsaturated fatty acid (n‐3 PUFA)‐rich fish oil (FO) around the breeding time improved the utero‐ovarian functions in the goat. Here, we investigated the effect of FO supplementation during the periparturient period on serum n‐3 PUFA, prostaglandin F_2α metabolite (PGFM), placental expulsion, uterine involution, resumption of oestrus and neonatal vigour. Rohilkhandi goat in advanced gestation (n = 16) was divided into two equal groups. One group was supplemented with FO containing 26% n‐3 long‐chain PUFA at the rate of 156 mg per kg body weight, while the control group was fed isocaloric palm oil (PO) from ?3 to +3 week of kidding. Dietary FO increased serum concentration of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by 7.3‐ and 6.6‐fold, respectively, after 6 weeks of supplementation. Goats in FO group expelled the foetal membranes 99.1 min earlier (p < .01) than those of PO group. Further, dietary FO significantly decreased the serum PGFM on day 7 post‐partum. However, no difference was found on uterine involution, which was complete by day 20 post‐partum in either group. Resumption of follicular activity by day 5 post‐partum was 87.5% in the FO as compared to 25% in the PO group (p < .05). Similarly, occurrence of behavioural oestrus by day 90 post‐partum was 57.1% in goats of the FO group while none of does was in the PO group (p < .01) expressed oestrus. It was concluded that feeding FO‐rich diet during ?3 to +3 weeks of kidding decreased the PGFM till day 7 post‐partum, hastened the expulsion of foetal membranes and reduced the time from kidding to first post‐partum oestrus in Rohilkhandi does.     

Apparent ileal digestibility of nutrients and amino acids in soybean meal,fish meal,spray‐dried plasma protein and fermented soybean meal to weaned pigs

This study sought to determine whether fermentation could increase apparent ileal digestibility (AID) of dry matter (DM), nitrogen (N), energy (E) and amino acids (AA) in fermented soybean meal (FSBM) greater than that of soybean meal (SBM) in weaned pigs. Four weaned pigs (10.00 ± 0.30 kg) were surgically equipped with T‐cannulas and randomly followed a 4 × 4 Latin square design of treatments (SBM, FSBM, fish meal and spray‐dried plasma protein). Overall, the fermentation process was able to reduce the amount of anti‐nutritional factors (ANF), including trypsin inhibitors, raffinose and stachyose, in the FSBM diet, which were significantly reduced by 39.4, 92.2, and 92.9%, respectively, as compared to the SBM diet. As a consequence of ANF reduction in FSBM, the AID of DM, N and E as well as AA was significantly greater with FSBM than SBM. Taken all together, the fermentation process improved the nutritional quality of SBM, due to ANF reduction, leading to improvement of digestibility of AA. As such, FSBM can be potentially used as a specialized feed ingredient, especially for young animal diets in an attempt to reduce diet costs.     

Effects of graded levels of liquid brewer's yeast on chemical composition and fermentation quality in cassava pulp and rice straw‐based total mixed ration silage

This study aimed to evaluate the effect of liquid brewer's yeast (LBY) addition on chemical composition and fermentation quality of mixture of LBY and cassava pulp (CVP) with rice straw (RS) in different ratios during preservation periods. Four mixtures of LBY, CVP and RS were made, that is mixture ratio of LBY : CVP : RS of 0% LBY, 20% LBY, 35% LBY and 50% LBY were 0:70:30, 20:50:30, 35:35:30 and 50:20:30 as fresh matter, respectively. The bags were opened at weeks 0, 1, 2, 4 and 8 after storage. The contents of dry matter, organic matter, crude protein (CP), ether extract (EE), neutral detergent fiber and acid detergent fiber ranged 36.4‐40.0, 88.9‐90.8, 4.0‐12.0, 1.1‐1.3, 58.8‐61.6 and 37.6‐40.0, respectively, and the contents of CP and EE increased and the other components decreased in proportion to LBY inclusion (P < 0.01). 50% LBY had the highest (P < 0.05) pH (4.81) and ammonia nitrogen per total nitrogen (NH₃‐N/TN) (7.40%) and the lowest V‐score (90.3). Propionic and butyric acid contents were 0.01% or lower in each mixture and storage period. There were rapid pH decrease and NH₃‐N/TN increase during the first week of the storage period. The increases of NH₃‐N/TN and acetic acid content and decreases of pH, lactic acid content and V‐score during the preservation were more drastic as LBY inclusion increased. Although higher proportion of LBY produced higher CP and lower fiber contents in the mixture, attention should be paid for the reduction of fermentation quality during longer storage periods.