Involvement of the VEGF signaling pathway in immunosuppression and hypoxia stress: analysis of mRNA expression in lymphocytes mediating panting in Jersey cattle under heat stress

BACKGROUND

Extreme panting under heat stress threatens dairy cattle milk production. Previous research has revealed that the gas exchange-mediated respiratory drive in critically ill dairy cattle with low O₂ saturation induces panting. Vascular endothelial growth factor (VEGF) signaling may play important roles in immunosuppression and oxidative stress during severe respiratory stress responses in heat-stressed cattle. The objectives of this study were to transcriptomically analyze mRNA expression mediating heat-induced respiratory stress-associated panting, evaluate gas exchange, screen hub genes, and verify the expression of proteins encoded by differentially expressed genes in lymphocyte pathways.

RESULTS

Jersey cattle were naturally heat-exposed. Physiological data were collected for response evaluation, and blood was collected for gas exchange and gene expression assays at 06:00, 10:00 and 14:00 continuously for 1 week. Lymphocytes were isolated from whole-blood samples for mRNA-seq and expression analysis of key pathway genes/proteins. The cattle respiration rates differed with time, averaging 51 bpm at 06:00, 76 bpm at 10:00, and 121 bpm at 14:00 (p < 0.05). Gas exchange analysis showed that both pH and pCO₂ differed with time: they were 7.41 and 41 mmHg at 06:00, 7.45 and 37.5 mmHg at 10:00, and 7.49 and 33 mmHg at 14:00, respectively (p < 0.01). Sixteen heat-related differentially expressed genes (DEGs; 13 upregulated and 3 downregulated) were screened between 212 DEGs and 1370 heat stress-affected genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) hub gene functional analysis annotated eleven genes to signal transduction, six genes to the immune response, and five genes to the endocrine response, including both prostaglandin-endoperoxide synthase 2 (PTGS2) and VEGF. Gene Ontology (GO) functional enrichment analysis revealed that oxygen regulation was associated with the phosphorus metabolic process, response to oxygen levels, response to decreased oxygen levels, response to hypoxia and cytokine activity terms. The main signaling pathways were the VEGF, hypoxia inducible factor-1(HIF-1), cytokine-cytokine receptor interaction and TNF pathways. Four genes involved Integrin beta 3 (ITBG3), PTGS2, VEGF, and myosin light chain 9 (MYL9) among the 16 genes related to immunosuppression, oxidative stress, and endocrine dysfunction were identified as participants in the VEGF signaling pathway and oxygenation.

CONCLUSION

These findings help elucidate the underlying immune and oxygen regulation mechanisms associated with the VEGF signaling pathway in heat-stressed dairy cattle.

Motivations for Industry Stakeholders in China, Vietnam, Thailand and Malaysia to Improve Livestock Welfare

Simple Summary

Animal welfare is a global issue that is important to civilians in many countries. Despite this, large gaps exist between practices as recommended by a scientific understanding of farm animal welfare; the expectations and understanding of society at large; and the realities within livestock industries across the world. The reasons for this are as numerous as they are challenging to overcome, however, understanding what might motivate key stakeholders to make improvements could form a base from which to begin. The livestock industry are arguably the most important stakeholders with the capacity to make meaningful choices that impact the welfare of animals, yet seldom are they consulted as to why they might make choices that either improve or threaten the welfare of the animals. This study aimed to collect information about the motivations and barriers to improve animal welfare from leaders in the livestock industry. A complex relationship of motivators is uncovered, and the importance of factors such as financial benefit and food safety is discussed. Figures are presented to begin illustrating the relationship between motivators. The findings of this study serve to better understand the motivations of livestock stakeholders in these key Asian nations, and the barriers that may prevent them from making choices that improve the welfare of the animals.

Abstract

Understanding what might motivate livestock stakeholders to improve animal welfare is useful information when developing initiatives that benefit from stakeholder engagement. This study was designed to assess the strength of motivating drivers in the development of attitudes to animal welfare, and the factors that impacted their ability to improve animal welfare. During a series of qualitative focus group sessions with livestock leaders across the same countries (Malaysia, China, Vietnam and Thailand), the current study presented livestock leaders (n = 139) with the most significant results in their country, and collected data pertaining to the meaning and applicability of these results. This data was then subject to thematic analysis to identify salient and repeated motivating factors and meanings. This process revealed a complex picture of relationships between motivators and the contexts that drive them. Figures are presented to begin illustrating these relationships. Some strong motivators were uncovered that were previously rated low in the survey (i.e., financial benefit) or not included at all (e.g., food safety). This paper also presents the opportunity to better understand the strength and relationship of extrinsic and intrinsic motivational forces behind animal welfare improvement.

Genetic associations between milk fat-to-protein ratio, milk production and fertility in the first two lactations of Thai Holsteins dairy cattle

The aims of this study were to estimate, simultaneously, the genetic parameters of test-day milk fat-to-protein ratio (FPR), test-day milk yield (MY), and days-open (DO) in the first two lactations of Thai Holsteins. A total of 76 194 test-day production records collected from 8874 cows with 8674 DO records between 2001 and 2011 from different lactations were treated as separated traits. The estimates of heritability for test-day FPR in the first lactation showed an increasing trend, whereas the estimates in the second lactation showed a U-shape trend. Genetic correlations for FPR-DO and MY-DO showed a decreasing trend along days in milk (DIM) in both lactations, whereas genetic correlations for FPR-MY increased along DIM in the first lactation but decreased in the second lactation. Genetic correlations of FPR between consecutive DIM were moderate to high, which showed the effectiveness of simultaneous analyses. Selection of FPR in the early stage has no adverse effect on MY and DO for the first lactation but has a negative effect on MY and positive effect on DO for the second lactation. This study showed that genetic improvement of the energy balance using FPR, MY and DO with multi-trait test day model could be applied in a Thailand dairy cattle breeding program.

Effect of milk fat to protein ratio on genetic variance for milk yield in Thai tropical Holstein cattle

The objective of this research was to investigate the optimum fat to protein ratio (FPR) in Thai tropical Holstein dairy cattle. First parity data consisting of 20 492 milk yields (MY) records for 24 891 cows for the period 2001 and 2011, were used in the analysis. The analysis used a random regression test-day animal model of third-order Legendre polynomials through the creation of a covariance function based on different FPRs. Variance components were estimated using the Bayesian method via the Gibbs sampling. The estimated heritability of MY in relation to FPR ranged from 0.19 to 0.27 with the pattern being similar to the genetic variances. Genetic correlations of MY at different FPRs were high at consecutive FPRs and then declined to negative in response to greater differences in FPR. Based on the results, it is concluded that the optimum FPR is in the range of 0.9 to 1.9, corresponding to the genetically controlled energy balance for MY in tropical Holsteins.

Milk protein profiles in response to Streptococcus agalactiae subclinical mastitis in dairy cows

The objective of this study was to investigate the milk protein profiles of normal milk and those of milk during the course of subclinical mastitis, caused by natural Streptococcus agalactiae infection. Two-dimensional gel electrophoresis and liquid chromatography mass spectrometry were used to assess protein profiles and to identify the proteins. The results showed that S. agalactiae subclinical mastitis altered the protein profiles of milk. Following Mascot database matching, 11 and 12 protein types were identified in the milk collected from healthy and S. agalactiae subclinical mastitic udders, respectively. The distinct presence of the antibacterial protein cathelicidin-1 was detected in infected milk samples, which in turn was highly correlated to the severity of subclinical mastitis as represented by the milk somatic cell count (r = 0.616), but not the bacterial count. The protein profile of milk reveals changes in the host response to S. agalactiae intramammary infection; cathelicidin-1 could therefore serve as a biomarker for the detection of subclinical mastitis in dairy cows.

Differences of skin morphology in Bos indicus, Bos taurus, and their crossbreds

Cutaneous evaporation is the main avenue by which cattle dissipate heat via the involvement of sweat glands and other skin components. The difference in skin morphology between B. indicus and B. taurus has been recognized, as well as differences in their ability to tolerate heat. The objective of this study was to compare skin morphology between B. indicus, B. taurus, and their crossbreds. Skin samples of Sahiwal (B. indicus) (n=10, reddish brown skin) and Holstein Friesian (HF) (B. taurus) (n=10, black and white skin) and crossbred of HF75% (n=10, black and white skin) and HF87.5 % (n=10, black and white skin) were biopsied for histological study, followed by measurement of skin components. The results indicated that breed significantly affected sweat gland morphology. The shape of the sweat gland, as indicated by the ratio of length/diameter, in Sahiwal was baggier in shape compared to HF (5.99 and 9.52) while values for crossbreds were intermediate (7.82, 8.45). The density and volume of sweat glands in Sahiwal (1,058 glands/cm(2); 1.60 μ(3) × 10(-6)) were higher than in HF (920 glands/cm(2); 0.51 μ(3)x10(-6)) and crossbreds, both HF 75 % (709 glands/cm(2); 0.68 μ(3) × 10(-6)) and HF 87.5 % (691 glands/cm(2); 0.61 μ(3) × 10(-6)) respectively. However, capillary surface area was greater for HF (2.07 cm(2)) compared to Sahiwal (1.79 cm(2)); accordingly, the lower genetic fraction of HF in crossbred cattle showed less capillary surface area (1.83 and 1.9 cm(2) for HF75% and HF87.5 %) (P<0.01). Nerve density was not significantly different between Sahiwal and HF but was higher in the crossbred (P<0.01) cattle. Moreover, the effect of skin color (black and white) was evaluated and it was found that there was an interaction (P<0.01) between breed and skin color on the skin components. This study reveals that there are differences in skin morphology among B. indicus, B. taurus and their crossbreds, with these differences being more or less related to the genetic fraction of HF. This may imply that capability for cutaneous evaporative heat loss and tolerance to heat in crossbred cattle could be related to skin morphology.

Detection of bovine leukocyte antigen DRB3 alleles as candidate markers for clinical mastitis resistance in Holstein x Zebu

Bovine leukocyte antigen DRB3 alleles from Holstein x Zebu crossbred dairy cows (n = 409) were analyzed using the PCR-RFLP technique. Exon II of DRB3 was amplified using locus-specific primers (HLO30/HLO32), followed by digestion with 3 restriction enzymes (RsaI, BstyI, and HaeIII). Forty alleles were found with frequency ranging from 0.005 to 0.139. The most frequently detected alleles of Holstein x Zebu were DRB3*16, *51, *23, *11, *8, and *1, accounting for 61.12% of the alleles in the population. Detection of candidate alleles for clinical mastitis occurrence was performed by logistic regression. It was found that percentage of Holstein fraction in crossbred cows had a nonsignificant effect (P > 0.05). However, parity had a significant effect on mastitis occurrence. In addition, DRB3*1 and *52 were the most associated with the occurrence of clinical mastitis, whereas *15, *51, and *22 were associated with resistance in crossbred populations. This is the first report of association of DRB3*15 and *51 with mastitis resistance. The association was validated by examining the candidate alleles in another commercial population. Highly susceptible (n = 43) and resistant (n = 42) groups of Holstein x Zebu cows were investigated. The result confirmed that DRB3*1 and *52 could be considered as susceptibility alleles, whereas *15, *51, and *22 could be considered as resistant alleles in Holstein x Zebu raised under tropical conditions. In addition, allele effects on 305-d milk production were estimated by BLUP. It was shown that most alleles associated with high clinical mastitis occurrence were related to increased milk yield. This study revealed that allele DRB3*10 had the greatest effect on increasing milk yield with moderate resistance to clinical mastitis, which could be used as a potential marker for selection in dairy genetic evaluation.

Influence of amount and type of dietary fat on deposition, adipocyte count and iodine number of abdominal fat in broiler chickens

This study described the relation between the type and amount of dietary fat on the deposition of abdominal fat by broiler chickens. It was hypothesized that at higher fat intakes, the well-known lowering effect of polyunsaturated fatty acids on the deposition of abdominal fat would be diminished. Experimental diets were formulated to contain three levels of added fat (3%, 6% and 9%). Each level had different proportions of the saturated fatty acids (SFA) and unsaturated fatty acids (UFA) by installing the ratios of 1:1, 1:2, 1:3, 1:4 and 1:5 with the use of tallow and soybean oil. Arbor Acres chicks, aged 7 days, were fed one of the 15 experimental diets until they were aged 42 days. Feed and water were provided ad libitum. There was no systematic effect of the dietary fat type and the amount on the weight gain and the feed intake. The lowest SFA:UFA ratio of 1:5 produced the lowest feed conversion rates, irrespective of the amount of the fat in the diet. The abdominal fat deposition was similar in the birds fed on diets containing either 3% or 6% added fat, but deposition was lower than in those fed 9% fat. A decrease in the SFA:UFA ratio of the diet was associated with a dose-dependent decrease in abdominal fat, irrespective of the amount of fat in the diet. This observation leads to the rejection of the hypothesis stated above. A decrease in the dietary SFA:UFA from 1:1 to 1:4 caused a decrease in the number of the fat cells per surface unit of breast meat. It is concluded that an increased intake of soybean oil at the expense of tallow reduced the abdominal fat deposition and the number of fat cells in the breast meat of broiler chickens.