With input costs continuously rising, the industry has been resourceful in using alternative ingredients to remain profitable. However, some of these feedstuffs contain unsaturated fat, which has brought the issue of pork fat quality to the forefront. Due to this, the industry is currently searching for a method to quantify the issue of pork fat quality and to further the understanding of how dietary fat influences the fat that is deposited in the pig.
A measurement known as iodine value (IV) has become the focal point of this conversation. Iodine value is used as a predictor of pork fat quality and can be measured two different ways: through an equation calculated from the concentration of six different unsaturated fatty acids, or directly by titrating the quantity of iodine that binds to double bonds or unsaturation in the fatty acid chain. The packing industry is looking at adopting this measurement as a standard of quality. However, despite its potential implementation throughout the industry, little research has been done on this measurement.
Additionally, understanding how dietary fat content affects the deposited fat in the pig throughout the growth cycle needs to be analyzed using a more definitive approach. Simply feeding alternative ingredients and measuring their impact on the final carcass iodine value is too simplistic, due to constant changes in the composition of alternative ingredients and due to the fact that excessive – and unnecessary – restrictions on the use of these alternative ingredients result in higher feed costs for pork producers. This, in turn, compromises the competitiveness of individual pork producers, as well as the industry as a whole.
Key takeaways from this project: dietary fat regardless of source increases feed efficiency and barn throughput, deposited fat becomes more reflective of the dietary fat source as the fat inclusion level is increased as de novo synthesis fat (saturated in comparison) becomes diluted, there is a significant difference in the degree of unsaturation as you move from the front to the back of the pig if the dietary fat inclusion level is less than or equal to 3%, which means that fat samples from the jowl will be higher than samples from the belly or loin, and as the pig matures and grows deposited fat becomes more saturated if the dietary fat source is not highly saturated. This research proves that dietary fat sources with an iodine value under 66 can be fed “limitless” without concern of impacting pork fat quality, but if a dietary fat source with iodine value greater than 122 is included at high levels carcass iodine values will be increased over the preffered packer standard of 74.
