Effect of feed texture, meal frequency and pre-slaughter fasting on carcass and meat quality, and urinary cortisol in pigs.
ABSTRACT Carcass and meat quality traits, and urinary cortisol variation was studied in 96 barrows assigned to the following treatments: feed texture (FT; mash vs. pellets), meal frequency (MF; 2 vs. 5 meals per day) and fasting time (F; 4, 14 and 24h) according to a 2×2×3 factorial design. Pigs fed mash, receiving feed five times a day and fasted for 24h before slaughter had lower carcass dressing yield (P<0.001). A higher (P<0.05) bruise score was found on carcasses from pigs fasted for 14 and 24h and fed either pelleted or mashed feed five times per day. The pH(u) value in the Longissimus muscle increased (P<0.05) with increasing fasting time, whereas in the Adductor muscle it was higher (P<0.05) in pigs fed with pellets in two meals per day and fasted for 24h. Urinary cortisol tended to be higher in pigs fasted for 14h compared to those fasted for 4 (P=0.10) and 24h (P=0.06). The results of this study show a significant influence of pellet feeding on carcass yield in fasted pigs, while the effects of pre-slaughter fasting time on meat quality traits were limited.
SourceAvailable from: Robert J Letcher[Show abstract] [Hide abstract]
ABSTRACT: Polar bears are heavily dependent on sea ice for hunting sufficient prey to meet their energetic needs. When the bears are left fasting, it may cause a rise in the levels of the stress hormone cortisol. Cortisol is the major corticosteroid hormone in most mammals, including polar bears. Production and regulation of this stress hormone are vital for the body as it is part of a myriad of processes, including in relation to metabolism, growth, development, reproduction, and immune function. In the present study, we examined the correlation between East Greenland polar bear hair cortisol concentration (HCC), a matrix that reflects longer-term hormone levels, and the fluctuations of the North Atlantic Oscillation (NAO) index, a large-scale climate phenomenon applied as a proxy for sea ice extent in the Greenland Sea along the coast of East Greenland. In doing so, a significant positive correlation (r = 0.88; p = 0.0004) was found between polar bear hair cortisol and the NAO, explaining 77 % of the variation in HCC observed between years over the period 1989–2009. This result indicates that interannual fluctuations in climate and ice cover have a substantial influence on longer-term cortisol levels in East Greenland polar bears. Further research into the implications and consequences inherent in this correlation are recommended, preferably across multiple polar bear populations.Polar Biology 10/2013; 36(10). DOI:10.1007/s00300-013-1364-y · 2.07 Impact Factor
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ABSTRACT: Cook, N. J. 2012. Review: Minimally invasive sampling media and the measurement of corticosteroids as biomarkers of stress in animals. Can. J. Anim. Sci. 92: 227�259. The measurement of corticosteroid hormones is commonly used as a biomarker of an animal’s response to stress. The difficulties in obtaining blood samples and the recognition of the stressor effect of blood sampling are primary drivers for the use of minimally invasive sample media. In mammals these include saliva, feces, urine, hair, and milk. In birds, samples include excreta, feathers, egg yolk and albumin. In fish, corticosteroids have been measured in excreta and swim-water. Each of these sample media incorporate corticosteroids in accordance with the processes by which they are formed, and this in turn dictates the periods of adrenocortical activity that each sample type represents. Cortisol in saliva represents a time-frame of minutes, whereas the production of feces may be hours to days depending on the species. The longest time-integrations are for hair and feathers which could be over a period of many weeks. The sample media also determines the structural changes that may occur via processes of conjugation to glucuronides and sulfides, metabolic conversion via enzymatic action, and bacterial breakdown. Structural changes determine the optimum methodologies used to measure corticosteroid hormones. In most sample media, measurement of a specific corticosteroid is a requirement depending on the species, e.g., cortisol in most mammals, or corticosterone in birds. However, in samples involving products of excretion, methodologies that measure a broad range of structurally related compounds are probably optimal. The utility of minimally invasive sample media as biomarkers of stress responses depends on the degree to which the corticosteroid content of the sample represents adrenocortical activity. Commonly, this involves comparisons between corticosteroid concentrations in blood plasma with concentrations in the alternative sample media. This review focuses on the methodological and biological validation of corticosteroid measurements in minimally invasive samples as biomarkers of adrenocortical responses to stress.Canadian Journal of Animal Science 09/2012; 92(3):227-259. DOI:10.4141/cjas2012-045 · 0.98 Impact Factor
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ABSTRACT: Ingested dietary nutrients and feed energy are partitioned among tissues to sustain body growth. Based on the respective costs of the various metabolic pathways allowing use and storage of feed energy into cells, it may be theorized that daily meal frequency could affect growth, body composition or feed efficiency. This study aimed to determine the effects of daily meal frequency on nutrient partitioning, tissue metabolism and composition, and growth performance. Young growing pigs (30 kg BW) were offered a same amount of feed either in two (M2, n = 15) or twelve (M12, n = 16) meals per day during a 3-week interventional period. Animals fed twice a day had an accelerated weight gain (+6.4%, P < 0.05) and exhibited a greater G:F (+4%, P = 0.03) than animals fed twelve meals per day during this period. Basal plasma concentrations of glucose, lactate, triglyceride, urea and leptin were lower (P < 0.001) in M2 pigs than in M12 pigs. Meal frequency also changed (P < 0.001) the time-course profiles of plasma concentrations of glucose, insulin and lactate in response to meal ingestion. A greater rise and a sharper fall in plasma glucose and insulin levels were observed in M2 pigs compared with M12 pigs. In both groups, similarities were observed in the postprandial time-courses of plasma concentrations of insulin and of alpha-amino nitrogen (used as a measure of total AA). Despite these metabolic responses, tissue lipids, glycogen content, and enzyme activities participating to energy metabolism in muscle and liver were similar (P > 0.10) in both groups at the end of the trial. Percentage of perirenal fat in the body and depth of dorsal subcutaneous fat tissue were not affected by meal frequency, but kidney weight was lower (-18%, P < 0.001) in M2 pigs than in M12 pigs. Altogether, the less frequent daily meal intake improves the conversion of feed into weight gain, without marked modifications of tissue composition in young pigs.Journal of Animal Science 03/2014; 92(5). DOI:10.2527/jas.2013-7505 · 1.92 Impact Factor