Supplementation with yak (Bos grunniens) bone collagen hydrolysate altered the structure of gut microbiota and elevated short-chain fatty acid production in mice

In this study, yak bone collagen hydrolysate(YBCH)was produced by mixed proteases and provided to standard-diet mice at a different dose(low dose(LD), medium dose(MD), and high dose(HD))to investigate its effects on the composition of gut microbiota and short-chain fatty acids(SCFA)production. It was found that YBCH was mainly composed of small molecular peptides whose molecular weight below 2 000 Da. Notably, supplementation with different doses of YBCH could significantly downregulate the ratio of Firmicutes to Bacteroidetes in the fecal microbiota. At the family level, the Lachnospiraceae abundance was significantly reduced in the YBCH gavage groups(mean reduction ratio 41.7 %, 35.2%, and 36.4% for LD, MD, and HD group, respectively). The predicted functions of gut microbes in the MD group were significantly increased at “lipid metabolism” and “glycan biosynthesis and metabolism”. Moreover, the SCFA production in the YBCH groups was elevated. Especially, the concentration of acetic acid, propionic acid, and butyric acid in the MD group was separately increased 79.7%, 89.2%, and 78.8% than that in the NC group. These results indicated that YBCH might be applied in the development of functional food for intestinal microecological regulation.

Potential antibacterial activity of berberine against multi drug resistant enterovirulent Escherichia coli isolated from yaks(Poephagus grunniens) with haemorrhagic diarrhoea

Objective:To evaluate the antimicrobial efficacy of berberine,a plant alkaloid.Methods:Five multi-drug resistant（MDR） STEC/EPEC and five MDR ETEC isolates from yaks with haemorrhagic diarrhoea were selected for the study.Antibacterial activity of berberine was evaluated by broth dilution and disc diffusion methods.The binding kinetics of berberine to DNA and protein was also enumerated.Results:For both categories of enterovirulent Escherichia coli（E.roli） isolates, berberine displayed the antibaclerial effect in a dose dependent manner.The MIC50 of berberine chloride for STEC/EPEC isolates varied from 2.07μM to 3.6μM with a mean of（2.95±0.33）μM where as for ETEC strains it varied from 1.75 to 1.96μM with a mean of（1.87±0.03）μM. Berberine bind more tightly with double helix DNA with Bmax and Kd of（24.68±2.62） and（357.8±57.8）,respectively.Berberine reacted with protein in comparatively loose manner with Bmax and Kd of（18.9±3.83） and 【286.2±113.6),respectively.Conclusions:The results indicate clearly that berberine may serve as a good antibacterial against multi drug resistant E.coli.

Comparison of rumen archaeal diversity in adult and elderly yaks(Bos grunniens)using 16S rRNA gene high-throughput sequencing

This study was conducted to investigate the phylogenetic diversity of archaea in the rumen of adult and elderly yaks. Six domesticated female yaks, 3 adult yaks((5.3±0.6) years old), and 3 elderly yaks((10.7±0.6) years old), were used for the rumen contents collection. Illumina Mi Seq high-throughput sequencing technology was applied to examine the archaeal composition of rumen contents. A total of 92 901 high-quality archaeal sequences were analyzed, and these were assigned to 2 033 operational taxonomic units(OTUs). Among these, 974 OTUs were unique to adult yaks while 846 OTUs were unique to elderly yaks; 213 OTUs were shared by both groups. At the phylum level, more than 99% of the obtained OTUs belonged to the Euryarchaeota phylum. At the genus level, the archaea could be divided into 7 archaeal genera. The 7 genera(i.e., Methanobrevibacter, Methanobacterium, Methanosphaera, Thermogymnomonas, Methanomicrobiu, Methanimicrococcus and the unclassified genus) were shared by all yaks, and their total abundance accounted for 99% of the rumen archaea. The most abundant archaea in elderly and adult yaks were Methanobrevibacter and Thermogymnomonas, respectively. The abundance of Methanobacteria(class), Methanobacteriales(order), Methanobacteriaceae(family), and Methanobrevibacter(genus) in elderly yaks was significantly higher than in adult yaks. In contrast, the abundance of Thermogymnomonas in elderly yaks was 34% lower than in adult yaks, though the difference was not statistically significant. The difference in abundance of other archaea was not significant between the two groups. These results suggested that the structure of archaea in the rumen of yaks changed with age. This is the first study to compare the phylogenetic differences of rumen archaeal structure and composition using the yak model.

Science of Camel and Yak Milks: Human Nutrition and Health Perspectives

Camels and yaks milks are rich in numerous bioactive substances that function beyond their nutritive value. Milk Camel milk is more similar to goat milk and contains less short-chain fatty acids than cow, sheep and buffalo milks, and about 3 times greater vitamin-C than cow milk. One kg of camel milk meets 100% of daily human requirements for calcium and phosphorus, 57.6% for potassium, 40% for iron, copper, zinc and magnesium, and 24% for sodium. Camel milk helps treat liver problems, lowers bilirubin output, lightens vitamin inadequacy and nutrient deficiency, and boosts immunity. Camel milk reduces allergies caused by cow dairy products. Camel milk has low milk fat made mainly from polyunsaturated fatty acids. It lacks ?-lactoglobulin and is rich in immunoglobulins, compatible with human milk. Yak milk has 16.9 - 17.7% solids, 4.9 - 5.3% protein, 5.5 - 7.2% fat, 4.5 - 5.0% lactose, and 0.8 - 0.9% minerals. Yak milk fat is richer in polyunsaturated fatty acids, protein, casein and fat than cow milk. Yak milk casein is used to produce antihypertensive peptides with capacities for producing value-added functional foods and proteins. Continual system-atic education of milk science especially for non-cow species will be an obligation for health implications to be optimally perceived by human populations worldwide.

Physiological and Biochemical Characteristics of Lactation in Half-lactating Yak

Yaks of two lactating types, the half-lactating yak and the total lactating yak, were investigated in their milk compositions, milk coagulation properties, and contents of three kinds of hormones, glucose,and protein in plasma. The half-lactating Maiwa yak and Jiulong yak contained significantly higher contents of protein, fat, and activities of alkaline phosphatase and γ-glutamyl transpeptidase in milk than that of the corresponding total-lactating yak breeds, with reduced milk yield and similar lactose level and relative percentages of main milk protein components. The half-lactatin yak resembled yaks in a late stage of lactation in their biochemical composition of milk; however, significant differences were also observed, which indicated that the former was in a special stage of lactation quite different from dairy cows. Milk of the total-lactating or halflactating yaks could be coagulated normally by adding chymosin, with a similar coagulation time. No significant difference was observed between prolactin and progesterone concentrations in plasma of the half-lactating yaks and total-lactating yaks; however, half-lactating yaks had significantly lower level of oestradiol-17 β in plasma than total-lactating yaks.

Comparative Analysis of Nutrient Components of Yak Milk from Different Regions

[Objective] To analyze the nutrient components of yak milk from different regions and provide a theoretical basis for further development and utilization of yak milk.[Method] A total of 150 yak milk samples were collected from Tianzhu County,Maqu County and Tianjun County,and 90 yak milk samples were collected from three different yak farms in Tianzhu County.The content of milk protein,milk fat,fat solid,non-fat solid and lactose,as well as the density,freezing point and acidity were determined,respectively.[Result] The milk protein content and milk fat content had significant differences between three regions.With the increasing altitude,the milk protein and milk fat were increased,but the content of fat solid,non-fat solid and lactose,density,freezing point and acidity had no obviously regular change.The milk protein content and milk fat content had no significant difference between three yak farms in Tianzhu County.[Conclusion] The altitude may affect the milk protein content and milk fat content of yak milk.

Morphological Observation on the Test and Epididymis in Hybrid of Wild and Domestic Yaks During the Growth Periods

This paper was carried out on the morphological character of the test and epididymis of three types of yak bull age 6,12,18,24 months old (1/2 wild yak, cross 1/2 wild yak and domestic yak). The results showed that the weight and size of testes and epidiymis was increased with the age which was hardly affected by imbalance of food supply during the cold and warm seasons. The development were similar for three kinds of yak at the same age(P＞0.05).

Complete Sequence of Yak Mitochondrial D-loop Region and Its Taxonomic Status in Bovinae

Primers based upon the mitochondrial genome sequences of Bos taurus were used to amplify and sequence the complete mitochondrial D-loop region of Jiulong yak(Poephagus grunniens).The results showed that the length of D-loop was 893 bp,with 87.4%homology to the Bos taurus D-loop sequence;there were 17 bp deletion.Using Ovis aries as an outgroup,the phylogeny of representative species of Bovinae(P.grunniens,P.mutus,Bos taurus,Bos indicus,Bison bison,Bison bonasus,and Bubalus bubalis)was analyzed.Among Bovinae,the sequence divergence between P.grunniens,P.mutus and American bison(Bison bison)was 6.2%-6.8%,which was less than that of Bos taurus and Bos indicus within Bos(10.0%-11.3%).Phylogenetic analysis found that P.grunniens,P.mutus and Bison bison clustered first of all,indicating there was higher genetic comparability among them than to that of Bos.Combining data from paleontology,morphology,and molecular biology,the present analysis supports the argument that Poephagus grunniens and Poephagus mutus should be classified as a distinct genus in Bovinae,that is Poephagus.

Isolation and Properties of Melanin in Fine Yak Hair

Melanin granules were isolated from fine yak hair by means of protein enzyme and hydrochloric acid.Resultsof SEM investigation and amino acid analysis were usedto study the physical and chemical properties of melaningranules.The solubility of melanin granules in differentchemical solutions was also studied.

Fluctuation of Body Size and Body Weight of Jinchuan Female Yak within One Year

To understand the exact changes in body size and body weight of Jinchuan female yaks within one year,the body size and body weight of 30 Jinchuan female yaks were measured from July 2015 to July 2016. The results showed that the body weight of Jinchuan female yak declined continuously since October 2015,and the weight loss in November 2015 was the largest. The body weight started to increase in May 2016,and the body weight increased significantly in June and July of 2016.

Study on the Milk Yield Pattern of Maiwa Yak

The change in lactation of Maiwa yak was studied based on the data of locating Maiwa yak in warm seasons during 2003- 2009. The results showed that the milk yield was increasing gradually during days 30- 70 after calving,reached the peak at days 70- 110,and decreased gradually to no milking whenafter. The milk yield of Maiwa yak was greatly influenced by lactation age rather than the yearly effect.

Development of a New Yak Breed Through Utilization of Wild Yak Genetic Rsource-seral Technologies for the Development of the Datong Yak Breed

On the Datong Yak Breeding Farm of Qinghai Province(Datong farm), the scientists of the Lanzhou Institute of Animal Science and Veterinary Pharmaceutics of Chinese Academy of Agricultural Sciences, in collaboration with others,explored the possibility to cross wild yak bulls with domestic yak cows in the past 20years and a new yak breed, the Datong yak, has been developed.

Quantitative Histology Studies on the Test in Hybrid Bull of Wild and Domestic Yak

The testicular tissue of three types of yak bull (1/2 wild yak,cross 1/2 wild yak and domestic yak) were studied quantitatively at 6,12,18 and 24 months old. The results showed that the average values changed from breed to breed at the same age. But there were no significant difference. The volume density and the height of seminiferous tubule and epithelium increased with the age and testicular weight. The capacity rate of the testicular seminiferous tubule in three types were 78.71% ,75.78% and 78.58% respectively, which nearly reached the level of mature bull.

Study on The Blood Physiological Indices of Wild Yak, Domestic Yak and Their Crossbreeds

Some blood physiological indices were determined in wild yak,Datong yak(the crossbreeds of the wild and domestic yak)and Tianzhu Black yak in a year. The red blood cell amount(RBC)and packed cell volume (PCV)of the wild yak and Datong yak were similar but differed largely from that of the Tianzhu Black yak. RBC of the wild yak and Datong yak were larger than that of the Tianzhu Black yak and their RBC varied seasonally.The results indicated that wild yak and Datong yak could effectively adapt to changes in environment by adjusting their physiological indices.

Growth and Development of The Kunlun Type of Wild Yak

The observation of body height and weight of 10 captured wild yak shows the body height and weight of the wild yak at three and four months old were similar with that of domestic yak. At their 24 months old, the body height and weight were higher by 26.9 % and 62.5 % than that of the domestic ones. The results indicate that, once adapted to the half-shed and half-grazing conditions, the tamed Kunlun type of wild yak with superior genetics would grow and develop faster than the domestic yak at elder ages.

Seasonal Changes in Forage Nutrients and Mineral Contents in Water Resources,Forage and Yak Blood

This paper reports results of a study conducted to investigate the concentrations of seven mineral elements in yak blood, forage and water resources around the Qinghai Lake in Qinghai Province in different seasons. Meanwhile, the nutritional compositions of the forage were also surveyed. The results suggest that the mineral elements and the forage nutrients change in a seasonal pattern. In yak blood,the sodium(Na)concentration varies from 0.291 to 0.034 mg/mL,and this is lower than the normal value. In the forage,the ratio calcium(Ca)to phosphorus(P)is 4.06～7.47:1 and potassium(K)to Na 30～27:1. These results indicate that the nutrition of the yak in the area is deficient in Na but high in K. For the withered forage sampled in February,the protein content is only 31.14% of the total protein in the forage growing at puerile stage in June. The severe loss of protein by 68. 9% and decrease of effective nutrients in the wintered forage are considered to be the reasons resulting in the poor condition of yak in winter and spring seasons.

Performance of Gannan Yak and Approaches for Improvement

At present, the yak population reached to 1.1 million in Gannan prefecture. Yak is dominant livestock in Gannan,and is the main source of herdsman income. In recent years, the population of Gannan yak continuously increased, but the performances such as body weight, dressing percentage and reproductivity are dropping.In order to improve quality, performance and economic benefits of yak production,it is very urgent to strengthen yak selective breeding.

Study on Intensity of Tissue Respiratory Metabolism in The Calves of Domestic Tak and Filial-generation of Wild Yak

The ITRM of liver, one of the important indexes of tissue respiratory metabolism in yak, is higher than other tissues. The relationship of ITRM and time belongs to the equation y = aebt. The ITRM of each tissue in reciprocal yaks were significant(P＜0.05) lower than that of the domestic yaks which showed that the adaptability to hypoxia of the reciprocal yaks were more powerful than the domestic yaks.

Endocrine Changes and Their Relationships with Body weight of Growing Yak

Concentrations of growth hormone (GH), insulin, thyroxin(T4 ) and 3,3 ' 5 '-tri-iodothyronine (T3)in blood samples of growing yak during different seasons were determined by radio-immunoassay.Changes in bodyweight of the growing yak and compositions of grass were also measured. The seasonal changes in hormones were significant (at least P＜0.05). In the same season, variation in hormonal concentration was affected by the growth stage of the animal. The bodyweight gains varied in different seasons, with significant increase from May to September and decrease from January to May. Correlation analysis indicated that T4 had a significant positive correlation with bodyweight of the growing yak(r= 0.323,P＜0.05) ,but other hormones did not have significant correlations with bodyweight. The results show that annual cycle of weight loss and gain is attributable to the seasonal changes in feed supply and that the seasonal changes in the concentrations of the assayed hormones were indirectly dependent on grass growth.

An Example of Yak Paternity Assignment by Microsatellite Genotyping

12 cattle microsatellite DNA markers were used for establishing the paternity of 4 Datong Yak calves.The results indicated that paternity can be assigned by use of exclusion method directely when the mother is clearly known and data of all likely sires were obtained. The more the alleles of a locus possessed, the more effectively the paternity can be assigned. Not only the microsatellite DNA marker is a promising tool in establishment of yak detail pedigrees, but also can provide us information of reproductive efficiency of the bull(s) based on the numbers of calves it produced in the herd, which will be useful in speeding up the processes of yak genetics improvement.