Simple SummaryThe fatty acid profile of pig backfat directly reflects the fatty acid profile of the pig diet. The increased intake of n-3 fatty acids, whose higher content is in vegetable oils, can decrease the risk of heart disease incidence and vascular disorders. The aim of this study was to evaluate the effect of rapeseed and soybean oils and the duration of supplementing the pig diet until slaughter on physical characteristics, fatty acid profile and lipid oxidation of backfat. With the supplementation of oil in the diet for 6 weeks until slaughter, the value of lightness and perforation part of backfat significantly decreased. A dose of 40 g/kg of rapeseed oil in the last 4 weeks before slaughter is sufficient for improving the fatty acid profile without adversely affecting the consistency of the backfat. From the point of view of human health, rapeseed oil is a more suitable source of unsaturated fatty acid than soybean oil in composing the diet for pigs.AbstractThis study compared the effect of two vegetable oils and their feeding duration on pig backfat quality. The experiment was conducted with 60 DanBred pigs that were fed a diet supplemented (40 g/kg) with rapeseed or soybean oil for 2, 4 or 6 weeks before slaughter at 152 d of age. The supplementation of both vegetable oils in the diets for 6 weeks negatively changed backfat consistency. The pigs fed soybean oil for 4 (17.64%) and 6 weeks (18.52%) before slaughter showed an increase in backfat linoleic acid content (p = 0.002), whereas, in contrast to the other groups, rapeseed oil in the diet for 6 weeks (2.38%) increased α-linolenic acid content (p = 0.039). The content of PUFAs (p = 0.024) and n-6 PUFAs (p = 0.003) was increased by adding soybean oil to the diet for 4 and 6 weeks. The ratio of n-6/n-3 PUFAs was decreased (p = 0.040) by supplementing rapeseed oil for 4 and 6 weeks. The oil feeding duration decreased (p < 0.001) the atherogenic and thrombogenic indices. The lipid oxidative stability of backfat stored for 3 and 5 days increased (p < 0.001) in pigs fed dietary vegetable oils for 6 weeks prior to slaughter. In conclusion, the feeding of rapeseed oil for 4 weeks before slaughter is sufficient for improving the FA profile without negative effect on the consistency of the backfat.

The objectives of this investigation were to examine the impact of the dietary inclusion of rapeseed and soybean oil and the length of their feeding before slaughter on growth performance, quantitative and qualitative carcass traits, and fatty acid composition in longissimus lumborum muscle (LLM) of pigs. The experiment was conducted with 72 pigs (36 barrows and 36 gilts), divided into six oil-containing diet groups and one control group. Diets of the experimental groups were supplemented with 4% rapeseed (ROD) or soybean (SOD) oil for six, four, and two weeks before slaughter. Diet of the control group had no oil supplement. Animals were fed ad libitum and slaughtered at average body weight of 115.8 kg. The oil supplement and feeding duration had a significant effect on fatty acid composition in intramuscular fat of LLM. The diet with both rapeseed and soybean oil significantly increased the content of linoleic acid and α-linolenic acid (ALA) in intramuscular fat. Both types of oil significantly increased total PUFA, n-3 PUFA, and the PUFA:SFA ratio. The significant decrease of n-6:n-3 PUFA ratio was observed in groups fed rapeseed oil for four and six weeks. Dietary addition of oils did not have any significant effect on average daily gain, carcass traits, and physical characteristics of LLM of pigs. However, daily feed intake and feed conversion ratio were reduced in the groups with soybean oil supplement. The results show that rapeseed oil supplementation (two weeks before slaughter) has positive effect on n-6:n-3 PUFA ratio and increase of ALA without negative effect on meat and fat quality.

Stupka R., Čítek J., Vehovský K., Zadinová K., Okrouhlá M., Urbanová D., Stádník L. (2017): Effects of immunocastration on growth performance, body composition, meat quality, and boar taint. Czech J. Anim. Sci., 62, 249-258.The study objective was to evaluate the effect of immunocastration in the period between the first and second vaccinations and subsequently between the second vaccination and slaughter on growth performance, carcass composition, meat quality, and boar taint, and compare results in immunocastrated males (IC), uncastrated boars (UCM), surgically castrated barrows (CM), and gilts (FE). The study included 70 pigs of the Duroc × (Large White × Landrace) crossbreed. Upon the overall assessment of the selected fattening indicators (average daily gain, feed intake), significant differences between CM and the other groups were demonstrated. Meanwhile, no significant differences were found between the IC, UCM, and FE groups. In this test, immunocastrates showed no negative effect from the second vaccination in relation to those carcass value indicators evaluated in comparison with UCM and FE. CM showed adversely lower carcass value parameters compared the other groups. No significant differences in pH, meat colour, drip loss, shear force, and intramuscular fat were found. The values of these indicators obtained for IC converged with those measured in UCM and FE. It was demonstrated that immunocastration prevented the occurrence of undesired boar taint. Androstenone decreased by 77% and skatole by 71% in IC as compared to UCM.

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