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Longitudinal muscle gene expression patterns associated with differential intramuscular fat in cattle
- N. J. Hudson, A. Reverter, P. L. Greenwood, B. Guo, L. M. Cafe, B. P. Dalrymple
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Intramuscular fat (IMF) can improve meat product quality through its impact on flavour and juiciness. High marbling cuts can command premium prices in some countries and grading systems, but there is substantial cost involved in choosing to grain feed animals in an effort to deposit more IMF. There would be value in developing methods to predict predisposition to ‘marble’ well. Unfortunately, the biological mechanisms underpinning marbling remain a mystery: the key adipocyte cell populations have not been defined, there are no reliable DNA markers, no known (if any) causal mutations and gene expression analyses in the main have tended to characterise increases in expression of end-point fat metabolism proteins such as the fatty acid-binding proteins. To shed light on expression-based markers of marbling potential, we contrasted LD gene expression in high IMF Wagyu cross animals with a low IMF Piedmontese cross at various time points. The expected divergence in the fat metabolism genes FABP4, THRSP, CIDEC and ACACA between the breeds occurs surprisingly late in postnatal development at about 20 months. On the other hand, divergent expression of WISP2, RAI14 and CYP4F2 was discovered in animals at or before 12 months of age, suggesting these genes may have potential as earlier predictors of marbling potential. In line with other researchers, we found intriguing links between IMF development and connective tissue remodelling. WISP2 – a novel adipokine highly expressed and secreted by adipose precursor cells and an inhibitor of the pro-fibrotic connective tissue growth factor – emerges as a particularly attractive candidate. It is relatively upregulated in high marbling Wagyu before admission to feedlotting, somewhere between 7 and 12 months. This difference is subsequently maintained until 25 months, but not thereafter. RAI14, thought to play a role in porcine adipocyte differentiation and with links to retinoic acid metabolism, has an unusual expression profile. Its expression level increases monotonically with postnatal development, and is always higher in Wagyu than Piedmontese. Strong, sustained upregulation of the anti-inflammatory CYP4F2 in Piedmontese is consistent with Wagyu adiposity being a pro-inflammatory state. Application of regulatory impact factor analysis, a network method for identifying causal effector molecules, suggests marbling roles for transcription factors previously implicated in (1) the formation of liposarcoma (unconstrained fatty masses) (YEATS4, MDM2), (2) adipogenesis (CREBL2, SP1, STAT1) and (3) inflammation (ISGF3G, HOXB13, PML).
The fate and behaviour of imbibed water in the rumen of cattle
- L. M. Cafe, D. P. Poppi
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- The Journal of Agricultural Science / Volume 122 / Issue 1 / February 1994
- Published online by Cambridge University Press:
- 27 March 2009, pp. 139-144
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The quantity of imbibed water that bypassed the rumen directly or rapidly effluxed from the rumen was investigated in four steers offered water marked with CrEDTA. Water was offered for short periods designed to simulate the drinking patterns that occur under extensive grazing conditions. Animals were fed either low quality pangola hay in the long form or a concentrate diet. Bypass of imbibed water was calculated by difference from marker imbibed and that present in the rumen on emptying after water had been imbibed. It thus represents the passage of marked water directly to the omasum/abomasum and that which rapidly effluxed from the rumen before emptying. Bypass of imbibed marked water was 19·0 and 25·3% for animals consuming pangola and concentrate respectively (significantly different from zero but no significant diet effect). Imbibed water entering the rumen mixed rapidly so that liquid from a posterior site in the rumen had a similar concentration of Cr to that from an anterior site in the proximity of the reticulum and cranial sac by about 1 h after drinking. There was no effect of rumen sampling site on the fractional outflow rate of CrEDTA (from imbibed marked water) from the rumen. It was concluded that most water which is drunk after a period of water deprivation will enter the rumen, mix rapidly and have a fractional outflow rate similar to other fluid in the rumen. The values derived may be used to calculate the amounts of supplement needed in drinking water if the target site is the rumen or intestines of cattle with intermittent access to water under extensive grazing conditions.
Prenatal and pre-weaning growth and nutrition of cattle: long-term consequences for beef production
- P. L. Greenwood, L. M. Cafe
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Severe, chronic growth retardation of cattle early in life reduces growth potential, resulting in smaller animals at any given age. Capacity for long-term compensatory growth diminishes as the age of onset of nutritional restriction resulting in prolonged growth retardation declines. Hence, more extreme intrauterine growth retardation can result in slower growth throughout postnatal life. However, within the limits of beef production systems, neither severely restricted growth in utero nor from birth to weaning influences efficiency of nutrient utilisation later in life. Retail yield from cattle severely restricted in growth during pregnancy or from birth to weaning is reduced compared with cattle well grown early in life, when compared at the same age later in life. However, retail yield and carcass composition of low- and high-birth-weight calves are similar at the same carcass weight. At equivalent carcass weights, cattle grown slowly from birth to weaning have carcasses of similar or leaner composition than those grown rapidly. However, if high energy, concentrate feed is provided following severe growth restriction from birth to weaning, then at equivalent weights post-weaning the slowly-grown, small weaners may be fatter than their well-grown counterparts. Restricted prenatal and pre-weaning nutrition and growth do not adversely affect measures of beef quality. Similarly, bovine myofibre characteristics are little affected in the long term by growth in utero or from birth to weaning. Interactions were not evident between prenatal and pre-weaning growth for subsequent growth, efficiency, carcass, yield and beef-quality characteristics, within our pasture-based production systems. Furthermore, interactions between genotype and nutrition early in life, studied using offspring of Piedmontese and Wagyu sired cattle, were not evident for any growth, efficiency, carcass, yield and beef-quality parameters. We propose that within pasture-based production systems for beef cattle, the plasticity of the carcass tissues, particularly of muscle, allows animals that are growth-retarded early in life to attain normal composition at equivalent weights in the long term, albeit at older ages. However, the quality of nutrition during recovery from early life growth retardation may be important in determining the subsequent composition of young, light-weight cattle relative to their heavier counterparts. Finally, it should be emphasised that long-term consequences of more specific and/or acute environmental influences during specific stages of embryonic, foetal and neonatal calf development remain to be determined. This need for further research extends to consequences of nutrition and growth early in life for reproductive capacity.