Some abstracts do not have video files because ASAS was denied recording rights.
1277
Milk metabolomics of dairy goats with mammary inflammation under heat stress conditions
The objective was to test whether mammary gland response to bacterial endotoxin could be conditioned by heat stress, and to detect biomarkers for heat stress and inflammation in milk. Eight multiparous Murciano-Granadina dairy (2.2 ± 0.1 L/d; 100 ± 5 DIM, 42 ± 2 kg BW) goats were maintained under 2 environmental conditions varying in temperature, relative humidity (RH) and temperature humidity index (THI): 1) 4 goats under thermoneutral (TN; 15 to 20°C, RH = 50 ± 5%, THI = 59 to 65), and 2) 4 goats under heat stress conditions (HS; 35°C from 0900 to 2100 and 28°C from 2100 to 0900, RH = 45 ± 5%, THI = 75 to 83). Adaptation of 11 d to the experimental treatments was allowed. On d 12 each animal had one udder half infused with 10 µg E. Coli lipopolysaccharide (LPS) and the other udder half as the control with 0.9% saline (CON). This resulted in 4 treatment combination: TN-CON, TN-LPS, HS-CON, and HS-LPS. Milk samples (0, 4, 6, 12, and 24 h) were collected and analyzed by 1H NMR spectroscopy operating at 600 MHz. Data were processed by the ChemoSpec package of R program and further analyzed by the web-based MetaboAnalyst program. Principal component analysis and partial least square–discriminant analysis were used to identify possible metabolite markers in milk. Citrate, glucose-1-phosphate, pyruvate and malonic acid increased in milk of HS goats. The increment in milk citrate might explain the previously observed deteriorated coagulation properties during the cheese making from the milk of heat-stressed animals. On the other hand, the LPS challenge resulted in an increment in milk lactate, acetate, butyrate, and capric acid. In conclusion, the metabolomic profile of milk was dramatically affected by environmental temperature and udder health status. Milk citrate and lactate were detected as good markers for heat stress and udder inflammation, respectively. Acknowledgement: Project AGL-2013-44061-R (Plan Nacional, MINECO, Spain).
Keywords: Metabolomics, Mastitis, Heat stress, Dairy goats