Impact of teat canal closure on the metagenomics profile of bacterial communities and its effect on udder health

Author(s)

José Augusto Ferronatto

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2021-04-20

Examining board members

Fernando Nogueira de Souza; Mônica Maria Oliveira Pinho Cerqueira; Marcos Bryan Heinemann

• Advisor: Alice Maria Melville Paiva Della Libera; Marcio Carvalho da Costa; Fernando Nogueira de Souza

Abstract

The present study aimed to evaluate the microbiota of the bovine mammary gland using high-throughput sequencing analysis of milk samples and assess their potential impact on the udder health. Thus, the study was divided into three axes: 1) determine the total and viable bacterial communities of aseptically collected milk samples; 2) evaluate the viable bacterial communities present in the milk collected from the teat canal as recommended by the National Mastitis Council or using a cannula, as well as, directly from the mammary gland cistern and mammary alveolus; and 3) the impact of the teat end occlusion in the prepartum period in nulliparous cows on viable bacterial communities of milk, and its impact on the udder health in the first month of lactation. In the first study, it was possible to identify that there was a reduction of 32.23% in the number of operational taxonomic units (OTUs) of viable bacterial communities in relation to total bacterial communities, due to the reduction in the abundance and number of Corynebacterium-OTUs, Rubrobacter-OTUs, Pseudomonas-OTUs and Wolbachia-OTUs, despite an increase in abundance and the number of Bacillus-OTUs. In the second study, it is possible to observe a greater number of OTUs in milk samples originated from traditional collection than those collected using a cannula, directly from the mammary gland cistern, and directly from the alveolus, although a lower abundance of Prevotella-OTUs was observed in the traditional collection in compared to the others. Finally, it was observed that the colostrum samples from teat ends considered closed resulted in a greater number of OTUs, as well as a greater number and abundance of Corynebacterium-OTUs. Colostrum samples with bacteriological negative results in the microbiological examination had a greater abundance of Bacillus-OTUs. Furthermore, udder quarters with low somatic cell count were associated with a greater abundance of Prevotellla- OTUs, while a greater number of Staphylococcus-OTUs and Streptococcus-OTUs were associated with a high somatic cell count. Therefore, the present study demonstrated that the total traditional collection can profoundly impact the results of the viable microbiota of milk samples, leading to misinterpretations, and consequently, it is essential to consider the milk sampling collection method and the use of propidium monoazide in bovine mammary gland studies of viable bacterial communities. Finally, our findings pointed out that the microbiome of the pre-partum period can affect the udder health, with the potential beneficial effect of bacteria of the Prevotella bacteria genus. (AU)

• FAPESP's process: 18/03685-8 - Impact of teat channel occlusion on the metagenomic profile and its reflex in health of the bovine mammary gland
• Grantee: José Augusto Ferronatto
• Support Opportunities: Scholarships in Brazil - Master