Caloric stress alters fat characteristics and Hsp70 expression in milk somatic cells of lactating beef cows

Abstract

Selection for higher production rate in cattle inhabiting challenging habitats may be considered disadvantageous because of possible deleterious effects on immunity and reproduction and, consequently, on calf crop percentage. In Israel, free-grazing high productive beef cows experience reduction in nutritional quality of forage during up to 8 months of the year. As milk production by dams dictates calf performance, dam's nutritional needs and rebreeding rates, the aim of the present study was to test how lactating beef cows deal with combined caloric and protein stress both at the productive and self protective levels. For this purpose, we studied the effect of long-term caloric stress on milk characteristics and gene expression of stress and milk components producing proteins. Lactating dams responded to caloric stress by decreased body weight, milk, and milk protein production. To compensate for total energy loses in milk, they produced milk of higher fat concentration and shifted the proportions of its fatty acids towards long and unsaturated ones. This was reflected by increased mRNA transcription of the fatty acid binding protein. Prolonged low-energy diet promoted cell-specific heat shock protein (Hsp) response; whereas significant increase of Hsp90 but unchanged levels of Hsp70 proteins were observed in white blood cells, the expression of Hsp70 in milk somatic cells was markedly attenuated, in parallel with a marked increase of α s1 -casein expression. At the mammary gland level, these results may indicate a decrease in turnover of proteins and a shift to an exclusive expression of milk components producing factors. Similar responses to caloric stress were revealed also in ketotic dairy cows. Ketosis promoted a shift towards long and unsaturated fatty acids and an increased expression of α s1 -casein in milk somatic cells. These findings may reflect an evolutionary-preserved mechanism in lactating cows for coping with caloric restriction. Overall, our results provide an index to test suitability of beef cattle breeds to inadequate caloric demands.

The Hsp72 response in peri-parturient dairy cows: relationships with metabolic and immunological parameters

“…Likewise, Yániz et al (2009) reported that conditions of mild hot did not affect Hsp72 concentrations in PBMC from early or mid-pregnant cows. Finally, no effect of summer heat stress was reported in the expression of Hsp70 in lymphocytes isolated from beef cattle (Eitam et al 2009) or dairy cows (do Amaral et al 2010). Therefore, values of summer THI recorded during the present study are likely to justify the lack of significant differences between SP and SU cows for the parameters under investigation.…”

“…Some studies demonstrated that caloric restriction, hypoglycaemia, or hyperlipidemia may differentially regulate Hsp expression in different body compartments. Eitam et al (2009) reported that a prolonged low-energy diet promoted cell-specific Hsp response in bovine with a significant increase of Hsp90 but unchanged levels of Hsp70 mRNA in white blood cells, and a lower expression of Hsp70 in milk somatic cells. Interestingly, Febbraio et al (2004) demonstrated that maintaining glucose availability during exercise attenuates the circulating Hsp72 response in healthy humans.…”

Caloric restriction and heart function: is there a sensible link?

“…Table 1 summaries some of the most important signaling molecules involved in CR-induced biological and physiological responses. FOXO ↓ [89,97] GSK-3β ↓ [93,98] HIF-1 ↓ [95,99] HSF-1 ↑ [94] HSP-70 ↑ [94,100] mTOR ↓ [90,101] NF-κB ↓ [81,82,95,97] PGC-1α ↑ [91,92] PPAR α ↑ [91,102] SIRT1 ↑↓ [92,93,103] ↑=increase in signal transduction; ↓=decrease in signal transduction.…”

Detection of Allelic and Genotypic Frequencies of Polymorphisms Associated with Meat Quality in the Mediterranean Baladi Cattle

“…Theoretically, the high frequency of GG genotype observed in BAL and Israeli SIM may partially be related to their adaptation to poor nutritional conditions, likely to occur in the Southern Mediterranean basin. Indeed, when lactating SIM cows were exposed to low energy and protein diet, they switched their milk fatty acids in favor of mono-and polyunsaturated ones [42].…”