Date Full Report Received
Date Abstract Report Received
A variety of energy sources are added to swine diets. These sources pressure the oxidative capacity of the body to varying degrees depending on their fatty acid profile. This affects the need for antioxidant vitamins and can affect animal health and performance as well as pork quality. The effect of fat source on the pig itself as well as the ultimate pork quality is a function of the amount of fat in the diet and the amount of time the pig is fed the different fat source. This impact will obviously increase then with heavier slaughter weights. This project evaluated the potential interaction of fat source and Vitamin E supplementation in pigs fed to a heavier slaughter weight of 150 kg (330 lb).
In Exp. 1, pigs were assigned to 8 dietary treatments in a 4 × 2 arrangement (see below graphic). Fat treatments included cornstarch (CS; a non-fat energy source), tallow (TW; a fat of intermediate saturation), corn oil (CO; a very unsaturated fat) and coconut oil (CN; a very saturated fat); the fats were added at 5%. Vitamin E (VE) supplementation was at 11 (the current NRC requirement estimate) and 200 IU/kg. This experiment was designed for proof of concept that there is an interaction between fat source and VE supplementation.
Pigs fed with CO had the highest plasma VE concentration throughout the experiment when diets were supplemented with 11 IU/kg VE; this is because CO has a fairly high level of VE naturally. However, in pigs fed 200 IU/kg VE, the plasma VE concentration increased linearly (P < 0.001) with increasing time and it increased faster (P < 0.05) in pigs fed with the CN and TW diets compared to pigs fed the CS and CO diets. Plasma VE content of pigs fed TW and CN supplemented with 200 IU/kg was actually greater than pigs fed CO by the midpoint of the experiment until the end of the experiment. Increasing dietary VE from 11 to 200 IU/kg also increased (P<0.001) the tocopherol concentration in both liver and loin muscle. However, no differences in ADG, carcass traits, subjective meat quality, and yield of Boston-butt, picnic-shoulder, and spare-rib were observed although increasing VE from 11 to 200 IU/kg improved ham yield (P < 0.05). Pigs from the TW group had the highest (P<0.05) total monounsaturated fatty acid content in the backfat, belly fat and liver while pigs from the CO group had the highest polyunsaturated fatty acid content resulting in the softest bellies as measured by the belly flop test and the highest iodine values in backfat and bellyfat. Pigs from the CO group had higher liver SOD activity (P=0.03) than the other treatments.
In Exp.2, pigs were assigned to 12 dietary treatments in a 2 × 6 factorial arrangement (see below graphic). Fat treatments were TW and CO. The VE treatments included four levels of α-tocopheryl-acetate (ATA – the industry standard; 11, 40, 100, and 200 ppm) and two levels of mixed tocopherols (primarily γ-tocopherol – used in some human applications; 40 and 100 ppm). This experiment was designed to evaluate more critically the form and supplemental level of VE that might provide the best response in the two principle fat sources used in the swine industry.
Increasing dietary ATA increased (P<0.001) plasma ATA concentration, while decreased (P<0.001) plasma γ-tocopherol concentrations at the end of all feeding phases. Increasing dietary ATA linearly increased overall ADG (P=0.02) from 28 to 150 kg. An interaction between fat sources and ATA was observed on cumulative ADG wherein pigs fed the corn oil diets, but not the tallow diets, had increased ADG with increased dietary ATA. Increasing dietary ATA also increased SOD activity (an antioxidant enzyme; P<0.05; highest at 100 ppm), and decreased MDA content (an oxidative product; P<0.05; lowest at 40 ppm) in the liver.
In summation, beneficial effects of dietary VE supplementation were observed on growth performance, antioxidant status, and meat oxidative stability of pigs, but not on carcass characteristic and meat color. Altering the dietary FA profile by the addition of different fat/oil sources affected meat quality related to the FA profile of fat tissues and liver. Interactions between fat sources and VE supplementation in plasma VE concentration and several other measurements were occasionally observed.
This project was funded by the National Pork Checkoff, the Fats and Protein Research Foundation, and DSM.
• Dietary VE supplementation improved growth performance, antioxidant status, and meat oxidative stability of pigs but not carcass characteristic and meat color in pigs grown to 150 kg.
• Dietary fat sources affected lean growth, fat deposition, belly firmness, pork oxidative stability, tissue fatty acid profile, and antioxidant status in pigs grown to 150 kg.
• Dietary VE supplementation interacted with dietary fat sources on plasma VE concentration. Plasma VE concentration generally increased with increasing time fed with 200 IU/kg VE, but it increased faster in pigs fed with supplemental tallow or coconut oil compared to pigs fed with supplemental corn oil or no supplemental oil.
• Dietary VE supplementation affected both liver and muscle tocopherol content but it affected liver tocopherol content (which would affect overall body antioxidant status) to a greater degree than muscle tocopherol content (which would affect pork quality).