广西水牛奶与荷斯坦牛奶工艺学特性比较

为了探索、比较广西水牛奶与荷斯坦牛奶的工艺学特性,对二者的缓冲容量、表面张力、粒度分布、稳定系数进行了比较分析。结果表明,广西水牛奶的缓冲容量和粒径分别是荷斯坦牛奶的1.1倍和2倍。在研究范围内,广西水牛奶在pH值为6.8时缓冲容量最大,温度50℃时表面张力最小,pH值为4.7时稳定系数最小;而荷斯坦牛奶在pH值为6.6时缓冲容量最大,温度为50℃时表面张力最小,pH值为4.6时稳定系数最小。广西水牛奶的粒径分布在91.28~458.7 nm之间,荷斯坦牛奶的粒径主要分布为91.28~190.1 nm之间,因此,认为两种牛奶的工艺学参数存在多方面的差异。     

Genome-wide association studies to identify quantitative trait loci affecting milk production traits in water buffalo

Water buffalo is the second largest resource of milk supply around the world, and it is well known for its distinctive milk quality in terms of fat, protein, lactose, vitamin, and mineral contents. Understanding the genetic architecture of milk production traits is important for future improvement by the buffalo breeding industry. The advance of genome-wide association studies (GWAS) provides an opportunity to identify potential genetic variants affecting important economical traits. In the present study, GWAS was performed for 489 buffaloes with 1,424 lactation records using the 90K Affymetrix Buffalo SNP Array (Affymetrix/Thermo Fisher Scientific, Santa Clara, CA). Collectively, 4 candidate single nucleotide polymorphisms (SNP) in 2 genomic regions were found to associate with buffalo milk production traits. One region affecting milk fat and protein percentage was located on the equivalent of Bos taurus autosome (BTA)3, spanning 43.3 to 43.8 Mb, which harbored the most likely candidate genes MFSD14A, SLC35A3, and PALMD. The other region on the equivalent of BTA14 at 66.5 to 67.0 Mb contained candidate genes RGS22 and VPS13B and influenced buffalo total milk yield, fat yield, and protein yield. Interestingly, both of the regions were reported to have quantitative trait loci affecting milk performance in dairy cattle. Furthermore, we suggest that buffaloes with the C allele at AX-85148558 and AX-85073877 loci and the G allele at AX-85106096 locus can be selected to improve milk fat yield in this buffalo-breeding program. Meanwhile, the G allele at AX-85063131 locus can be used as the favorable allele for improving milk protein percentage. Genomic prediction showed that the reliability of genomic estimated breeding values (GEBV) of 6 milk production traits ranged from 0.06 to 0.22, and the correlation between estimated breeding values and GEBV ranged from 0.23 to 0.35. These findings provide useful information to understand the genetic basis of buffalo milk properties and may play a role in accelerating buffalo breeding programs using genomic approaches.     

Odor composition of preferred (buffalo and ox) and nonpreferred (waterbuck) hosts of some Savanna tsetse flies

A previous study on the feeding responses of tsetse flies, Glossina morsitans morsitans, implicated the existence of allomonal barriers, both volatile and nonvolatile, on the nonpreferred host, waterbuck, Kobus defassa. In the present study, electroantennogram-active compounds in odors from waterbuck were compared with those of two preferred hosts of tsetse flies, buffalo, Syncerus caffer, and ox, Bos indicus. Odors from the three bovids were trapped on activated charcoal and/or reverse-phase (octadecyl bonded) silica and analyzed with a gas chromatography-linked electroantennographic detector (GC-EAD) and, where possible, identified by using gas chromatography-linked mass spectrometry (GC-MS) and chromatographic comparisons with authentic samples. The GC-EAD profiles (with G. m. morsitans antennae) of the odors of the two preferred hosts were comparable, comprising medium-chain, saturated or unsaturated aldehydes and phenols, with buffalo emitting a few more EAG-active aldehydes. Waterbuck odor gave a richer profile, consisting of fewer aldehydes but more phenolic components and a series of 2-ketones (C₈–C₁₃) and -octalactone. This bovid also emits moderate amounts of C₅–C₉ straight-chain fatty acids, some of which were detected in buffalo and ox only in trace amounts. However, these did not elicit significant GC-EAD responses. Waterbuck profiles from the antennae of G. pallidipes showed broad similarity to those from G. m. morsitans, although the composition of aldehydes and ketones was somewhat different, indicating species-specific difference in the detection of host odors. Certain waterbuck-specific EAG-active components, particularly the 2-ketones and lactone, constitute a candidate allomonal blend in waterbuck odor.     

Behavior and milk production of buffalo cows as affected by housing system

To verify the effect of 2 housing systems (with and without a pool and an ample outdoor lot) on behavior and milk yield, 45 lactating buffalo cows were group-housed in a free stall open-sided barn with concrete floor where they received 10 m²/head as space allowance (group NP); 43 cows were group-housed in a similar barn, but had access to an outdoor yard (36 m²/head) and a concrete pool of 208 m² (group WP). Animals were subjected to 8 sessions of instantaneous scan sampling at approximately 10-d intervals. Behavioral variables were expressed as proportions of subjects observed in each category of posture and activity. In addition, rapid behaviors such as agonistic, social, and reproductive interactions, social licking, and self-grooming were recorded continuously. These variables were expressed as number of interactions per animal. At the end of each hour of observation, temperature and relative humidity were recorded. In WP the proportion of animals observed wallowing was 0.476 ± 0.034, whereas lower proportions were observed standing (0.389 ± 0.029) or lying (0.141 ± 0.021) outside the pool. In NP the proportions of animals observed standing and lying were 0.452 ± 0.042 and 0.548 ± 0.042, respectively. A significant relationship between mean temperatures recorded on observation days and proportion of animals in the pool was observed (r_s = 0.41). Fewer animals from group WP were observed idling compared with buffaloes from group NP (0.44 ± 0.024 vs. 0.509 ± 0.024, respectively), whereas more WP animals were involved in investigative activities than NP cows (0.099 ± 0.009 vs. 0.042 ± 0.009, respectively). A greater number of social interactions (sniffing and nuzzling) and social lickings were observed in group WP than in group NP (0.120 ± 0.010 vs. 0.067 ± 0.010, and 0.151 ± 0.018 vs. 0.090 ± 0.018, respectively). The WP buffalo cows had a greater milk yield than NP cows (11.73 ± 0.31 vs. 10.78 ± 0.28 kg/d, respectively), whereas no differences between groups were observed for protein (4.86 ± 0.04 vs. 4.80 ± 0.03% for WP and NP, respectively) and fat contents (8.49 ± 0.14 vs. 8.38 ± 0.13% for WP and NP, respectively). We conclude that the provision of a pool and an ample outdoor paddock can have beneficial effects on welfare and milk production of buffaloes.     

Use of nisin, lysozyme and EDTA for inhibiting microbial growth in chilled buffalo meat

The effect of nisin, lysozyme and lysozyme combined with disodium ethylenediaminetetraacetate salt (EDTA) for inhibiting the growth of spoilage micro‐organisms in buffalo meat was investigated. Prior to packaging, the samples were alternatively dipped in solutions containing different concentrations of nisin, lysozyme and combinations of a pre‐fixed amount of lysozyme and different concentrations of EDTA. The packed meat samples were stored at 4 °C, and the microbial changes were monitored for a period of 8 days. The best results, in terms of microbial shelf‐life extension, were obtained by dipping the meat steaks in a solution containing a combination of 0.5% of lysozyme and 2% of EDTA. This treatment was able to reduce the growth of all the investigated bacteria and showed a bactericidal effect on Brochotrix thermosphacta during the entire period of storage.     

Marker discovery and associations with β-carotene content in Indian dairy cattle and buffalo breeds

Vitamin A is essential for human health, but current intake levels in many developing countries such as India are too low due to malnutrition. According to the World Health Organization, an estimated 250 million preschool children are vitamin A deficient globally. This number excludes pregnant women and nursing mothers, who are particularly vulnerable. Efforts to improve access to vitamin A are key because supplementation can reduce mortality rates in young children in developing countries by around 23%. Three key genes, BCMO1, BCO2, and SCARB1, have been shown to be associated with the amount of β-carotene (BC) in milk. Whole-genome sequencing reads from the coordinates of these 3 genes in 202 non-Indian cattle (141 Bos taurus, 61 Bos indicus) and 35 non-Indian buffalo (Bubalus bubalis) animals from several breeds were collected from data repositories. The number of SNP detected in the coding regions of these 3 genes ranged from 16 to 26 in the 3 species, with 5 overlapping SNP between B. taurus and B. indicus. All these SNP together with 2 SNP in the upstream part of the gene but already present in dbSNP (https://www.ncbi.nlm.nih.gov/projects/SNP/) were used to build a custom Sequenom array. Blood for DNA and milk samples for BC were obtained from 2,291 Indian cows of 5 different breeds (Gir, Holstein cross, Jersey Cross, Tharparkar, and Sahiwal) and 2,242 Indian buffaloes (Jafarabadi, Murrah, Pandharpuri, and Surti breeds). The DNA was extracted and genotyped with the Sequenom array. For each individual breed and the combined breeds, SNP with an association that had a P-value <0.3 in the first round of linear analysis were included in a second step of regression analyses to determine allele substitution effects to increase the content of BC in milk. Additionally, an F-test for all SNP within gene was performed with the objective of determining if overall the gene had a significant effect on the content of BC in milk. The analyses were repeated using a Bayesian approach to compare and validate the previous frequentist results. Multiple significant SNP were found using both methodologies with allele substitution effects ranging from 6.21 (3.13) to 9.10 (5.43) µg of BC per 100 mL of milk. Total gene effects exceeded the mean BC value for all breeds with both analysis approaches. The custom panel designed for genes related to BC production demonstrated applicability in genotyping of cattle and buffalo in India and may be used for cattle or buffalo from other developing countries. Moreover, the recommendation of selection for significant specific alleles of some gene markers provides a route to effectively increase the BC content in milk in the Indian cattle and buffalo populations.