Improvement of subcutaneous fat quality of pigs by means of dietary manipulation

[摘要] English: The objectives of this study were to identify feed ingredients with the potential to improve fat qualityof pigs and to illustrate experimentally that it is possible to produce baconer pigs in the P and 0classification groups with good fat quality.A questionnaire was sent to animal feed companies in South Africa to identify individual feedingredients available as well as typical inclusion levels of such ingredients. All available lipidcontaining feed ingredients were then analyzed for iodine value and fatty acid composition. From thisdata, individual feedstuffs with the potential of improving fat quality was identified. A diet wasformulated with the aim of improving fat quality of pigs cost effectively. A feeding trial wasperformed, comparing a control diet with the one optimized for fat quality. Fourteen Large White xDuroc gilts weighing on average ± 43 kg were randomly divided into two groups of seven pigs eachand assigned to either the control or experimental diet. Pigs were provided with ad libitum access tofeed and water. Feed intake was measured daily and weight was recorded every week. At ± 95 kg .live weight the pigs were slaughtered. Firmness of the subcutaneous fat was measured and colour ofthe backfat was determined. Lipid quality characteristics were determined on control andexperimental pigs and compared with international guidelines for good fat quality. Differences inparameters between treatments were statistically compared.102The first objective of this experiment, namely the formulation of an experimental diet with thepotential to improve the backfat quality of pigs, was successfully achieved. The experimental diet hada more saturated fatty acid profile than the control diet as indicated by iodine value and fatty acidanalysis. No significant differences (P > O.O~) were observed in growth performance and carcasscharacteristics between the control and experimental groups. All pig carcasses were classified aseither P or 0 carcasses. Minolta colour measurements (L*, a*, and b* values) of the backfat did notdiffer significantly (P > 0.05) between the control and experimental group. The fat hardnessmeasurement of the experimental group was significantly higher (P < 0.01) than that of the contro 1group, indicating that backfat from the experimental group was firmer than that of the control group.The same significant (P < 0.001) trend was observed in refraction index value with refraction indexof backfat from the experimental group lower than the internationally proposed maximum of 1.4598while the control group had a value higher than 1.4598. A significant difference (P < 0.001) was also observed in backfat iodine value with the experimental group having an iodine value lower than theinternationally proposed maximum of 70 and the control group having a value higher than thismaximum. Anatomical differences was found in subcutaneous fat saturation. Backfat had higheriodine values (more unsaturated) than subcutaneous fat in the belly area (more saturated). As far asthe fatty acid composition were concerned, the experimental group had a significantly higher (P<0.001) content of saturated fatty acids (C16:0 and C18:0) than the control group. Linoleic acidcontent of subcutaneous fat from the experimental group was lower than the internationallyproposed maximum of 15 % while C18:2 content of the control group was higher than thismaximum. These fatty acid differences were also reflected in the fatty acid ratios and resulted in theexperimental group conforming to most international guidelines for fat quality. The experimentalgroup conformed to the following international guidelines for fatty acid ratios while the controlgroup did not: total trienoic fatty acids, total penta- + hexaenoic fatty acids, total UFA, total PUFA,C18:0/C18:2 ratio and double bond index.

[发布机构] University of the Free State