The effects of olive pomace on the fatty acid profile and weight gain in Capra aegagrus hircus as a model for ruminants



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In the livestock industry, feed is one of the highest variables affecting the cost of production. Olive pomace is a by-product of the olive oil industry and could be considered as a potential livestock feedstuff to be used as an energy supplement due to its high fat content (15%) and can potentially alter the biochemical composition of blood and muscle tissue. This project was split into two phases; the objective of phase I was to determine if olive pomace could be used as an acceptable low cost feedstuff to maintain weight during the colder winter months. To accomplish this, 28 Spanish influenced goats were fed (2% of body weight, BW) varying amounts of fermented pomace with a protein pellet to meet NEm requirements. The four test groups (n=7) consisted of a 3:1, 1:1, and 1:3 olive pomace to concentrate ratio (O:C) as well as a control containing no pomace. All groups received molasses at 0.5% BW to improve the palatability of the feed and to further homogenize the ration to discourage selective eating of the mixture. Does were fed in herring bone style runs every morning for 49 days. The average daily gain (ADG) for the 1:3, 1:1, 3:1 and control groups were 0.0370, 0.0166, 0.0119, and 0.0262 kg/day, respectively with no difference detected between groups (P>0.88). A difference (P<0.001) in consumption rates was detected between treatments with the 3:1 group consuming more feed with an average of 0.785 kg/day compared to the control at 0.694 kg/day. Additionally, olive pomace may be consider as a cost effective supplement to reduce costs for maintenance rations. Ration costs were calculated at $0.153/kg for the 3:1 ration compared to $0.6386/kg for the pelleted control ration. On average, this difference in input cost can reduce a producer’s cost of feed by $13.53/hd over a 49 day maintenance feeding period (P<0.001) by feeding olive pomace. The objective of phase 2 was to determine if olive pomace could be supplemented at a level that increases the C18:1 concentration in blood. Mature Spanish-influence goats (n=14; 41.6 kg) were fed ad libitum olive pomace, starting at 2% of their BW for 28 days to determine if this by-product would alter circulating fatty acid content. Molasses was mixed with the ration at 0.5% BW to improve the palatability of the feed. Does were fed in herringbone-style runs every afternoon and BW and blood samples were collected every two weeks. There were significant changes in C18:1 and C18:2 over time with mean consumption of 0.55 kg/d over the duration of the trial. From d 0 to d 28, the serum concentration of C18:1 increased (P<0.001) by 8.67% and C18:2 increased (P<0.03) by an average of 4.38%. Serum concentration of C18:0 increased by 3.59% but this was not significant. There was also no significant increase in C16:0. If C18:1 is deposited in the muscle tissue as a result of increased concentration in the blood, then feeding olive pomace can be a healthy alternative to high starch ingredients such as corn and barley.