Essential oils (EO) and short-chain fatty acids have potential antimicrobial activity in broilers. This study aimed to investigate the effect of a sp

A total of 1304 goat udder halves were sampled monthly during an entire lactation (6262 samples) with the aim of identifying factors affecting milk somatic cell count (SCC). Bacteriological analyses for identification of mastitis pathogens were carried out on all samples and SCC was also determined. All animals were examined for infection by caprine arthritis-encephalitis virus (CAEV) using a commercial ELISA test kit. Results obtained were arranged in two databases (whole-lactation average half-udder database and monthly half-udder database) and two mixed models were applied. Random effects of half udder nested into flock and fixed effects of flock, intramammary infection (IMI) status, number of kids born, length of lactation and interaction of parity with IMI status were significant for the first database. CAEV infection and its interaction with IMI status was not significant. Milk SCC was significantly increased for infected udder halves and milk from udder halves infected with minor pathogens had lower SCC than udder halves infected with major pathogens. For healthy udder halves, SCC was higher in older animals but this effect was not evident in halves with IMI. Multiple birth and short-duration lactation were factors associated with elevated milk SCC. The second mixed model considered repeated measures in time for consecutive samplings throughout lactation (stage of lactation) which was also a significant factor with increasing stage of lactation. The influence of all these factors should be taken into account in the establishment of more reliable diagnostic SCC thresholds for IMI.

Two hundred ten Californian x New Zealand White rabbits were used to study the influence of diet and slaughter weight (2.0, 2.25, and 2.5 kg) on feed intake, growth, feed efficiency, carcass characteristics, and body chemical composition. Seven diets were formulated to contain 24% ADF: Diet C (control) had no added fat; Diets T, O, and S contained 3% of added beef tallow, oleins, and soybean oil, respectively; Diets TWS, OWS, and SWS contained the same level and types of fat plus 18% heated whole soybeans (WS) to increase the dietary fat by 3%. Fat addition did not affect ADG or dressing percentage, but it improved feed:gain ratio (.06 for each 1% of dietary fat, P < .001). Although the main measurements of carcass were not influenced by fat addition, the rabbits fed diets containing the highest fat percentage had the highest weights of perirenal (P < .001) and scapular (P < .01) depots and the highest body fat content (P < .01). The increase in slaughter weight improved all the desirable carcass characteristics measured but imparied feed:gain (by 13%, P < .001). Increasing slaughter weight also increased the perirenal and scapular fat depots by 40 an 24%, respectively (P < .001)< and the body fat content by 28% (P < .01). There were no differences in the utilization of animal and vegetable fats, and only for some traits ADG, feed intake, kidney weights) did the diets with soybean oil result in better responses than those with oleins. The results indicate that fat addition to fibrous diets extends the rabbit's growing period without impairing the feed:gain ratio. The joints of rabbits killed at heavier weights have more desirable weights for marketing the carcass on a retail cut basis. Copyright © . .

Methionine (Met) and arginine (Arg) regulate casein protein abundance through alterations in activity of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway. A potential role for the circadian clock network on the regulation of protein synthesis, partly via activity of mTORC1, has been highlighted in non-ruminants. The main objective of the study was to determine in ruminant mammary cells alterations in mRNA, protein abundance and phosphorylation status of mTORC1-related upstream targets, circadian clock proteins, and protein kinase AMP-activated catalytic subunit alpha (AMPK) in relation to α-s1-casein protein (CSN1S1) abundance in response to greater supply of Met and Arg alone or in combination. Primary bovine mammary epithelial cells (BMEC) were incubated for 12 h in a 2 × 2 arrangement of treatments with control media (ideal profile of amino acids, IPAA), or media supplemented with increased Met (incMet), Arg (incArg), or both (incMet + incArg). Data were analyzed testing the main effects of Met and Arg and their interaction. Among 7 amino acid (AA) transporters known to be mTORC1 targets, increasing supply of Arg downregulated SLC1A5, SLC3A2, SLC7A1, and SLC7A5, while increasing supply of Met upregulated SLC7A1. mRNA abundance of the cytosolic Arg sensor (CASTOR1) was lower when supply of Arg and Met alone increased. p-TSC2 (TSC complex subunit 2) was greater when the Arg supply was increased, while the phosphoralation ratio of p-AKT (AKT serine/threonine kinase 1):total (t) AKT and p-AMPK:tAMPK were lower. In spite of this, the ratio of p-mTOR:tmTOR nearly doubled with incArg but such response did not prevent a decrease in CSN1S1 abundance. The abundance of period circadian regulator 1 (PER1) protein nearly doubled with all treatments, but only incMet + incArg led to greater clock circadian regulator (CLOCK) protein abundance. Overall, data suggest that a greater supply of Met and Arg could influence CSN1S1 synthesis of BMEC through changes in the mTORC1, circadian clock, and AMPK pathways. Identifying mechanistic relationships between intracellular energy, total AA supply, and these pathways in the context of milk protein synthesis in ruminants merits further research.