Two studies were conducted to evaluate potential impact of high and low energy diets and also ratio of linoleic and alpha-linolenic acids on joint health. The first study evaluated the impact of feeding high energy (3.55 ME Kcal/kg) and low energy (3.29 ME Kcal/kg) diets to grow-finish swine. Within each energy level, the pigs were fed either a diet containing 23:1 or 12:1 linoleic:linolenic acid ratio. The 23:1 ratio would be similar to that of a common United States corn/soybean meal/distiller’s grain finishing ration. Pigs receiving the high energy diets had increased final body weight, average daily gain and improved feed efficiency. Gilts receiving diets the 12:1 linoleic:linolenic acid ratio had similar final body weight to barrows and increased average daily gain compared to gilts fed the 23:1 ratio.The low energy diet tended to reduce inflammatory markers in joint fluid collected from the hock and carpus joints. In the second study, pigs were fed an equal energy level with differing inclusions of linoleic acid and linoleic:linolenic acid ratios. Pigs were provided either a high (30 g/kg) or low (15 g/kg) linoleic acid level with a high (20:1), moderate (12:1) or low (4:1) linoleic:linolenic acid ratio. The 4:1 ratio would be similar to what has been reported to reduce joint inflammation in humans and dogs. Gilts receiving a high linoleic:linolenic acid ratio (20:1) had increased body weight and average daily gain compared to gilts receiving the other ratios. Inflammation marker concentrations decreased as the pigs grew in weight; however, the diets did not impact the level of inflammation in either the hock or carpus joint fluid.
To conclude, the high and low linoleic:linolenic ratios can be fed at varying energy and linoleic acid levels without impacting growth. Feeding a 4:1 linoleic:linolenic acid ratio does not appear to alter joint inflammation in swine. The linoleic:linolenic ratio can impact the growth of gilts and the use of lower energy diets does appear to reduce joint inflammation. In addition, as the pig matures, inflammation within the joint appears to decline indicating that any potential impact of diet on reducing joint inflammation needs to occur during periods of rapid growth.