Dry Matter Intake is Decreased More by Abomasal Infusion of Unsaturated Free Fatty Acids than by Unsaturated Triglycerides

Abstract

Previous experiments from our group have demonstrated that abomasal infusion of unsaturated free fatty acids (FFA) markedly decreases dry matter intake (DMI) in dairy cows. In contrast, experiments from other groups have noted smaller decreases in DMI when unsaturated triglycerides (TG) were infused postruminally. Our hypothesis was that unsaturated FFA would be more potent inhibitors of DMI than an equivalent amount of unsaturated TG. Four Holstein cows in late lactation were used in a single reversal design. Cows were fed a total mixed ration containing (DM basis) 23% alfalfa silage, 23% corn silage, 40.3% ground shelled corn, and 10.5% soybean meal. Two cows received soy FFA (UFA; 0, 200, 400, 600 g/d) and 2 received soy oil (TG) in the same amounts; cows then were switched to the other lipid source. Cows were abomasally infused with each amount for 5-d periods. The daily amount of lipid was pulse-dosed in 4 equal portions at 0600, 1000, 1700, and 2200 h; no emulsifiers were used and there was no sign of digestive disturbance. Both lipid sources linearly decreased DMI, with a significant interaction between lipid source and amount. Slope-ratio analysis indicated that UFA were about 2 times more potent in decreasing DMI than were TG. Decreased DMI led to decreased milk production. Milk fat content was increased linearly by lipid infusion. Milk fat yield decreased markedly for UFA infusion but was relatively unaffected by infusion of TG. Contents of short- and medium-chain fatty acids in milk fat decreased as the amount of either infusate increased. Contents of C(18:2) and C(18:3) in milk fat were increased linearly by abomasal infusion of either fat source; cis-9 C(18:1) was unaffected. Transfer of infused C(18:2) to milk fat was 35.6, 42.5, and 27.8% for 200, 400, and 600 g/d of UFA, and 34.3, 39.6, and 34.0% for respective amounts of TG. Glucagon-like peptide-1 (7-36) amide (GLP-1) concentration in plasma significantly increased as DMI decreased with increasing infusion amount of UFA or TG. Plasma concentration of cholecystokinin-octapeptide (CCK-8) was unaffected by lipid infusion. These results indicate that unsaturated FFA reaching the duodenum are more potent inhibitors of DMI than are unsaturated TG; the effect may be at least partially mediated by GLP-1.

Production performance and pattern of milk fat depression of high-yielding dairy cows supplemented with encapsulated conjugated linoleic acid

“…Moreover, increased amounts of unsaturated FA infused to the abomasum (Bremmer et al, 1998) or fed to dairy cows (Harvatine and Allen, 2005;Moallem et al, 2007) have been shown to decrease the feed intake. Litherland et al (2005) showed a negative correlation between DMI and plasma concentrations of glucagon-like peptide 1 amide (7 to 36; GLP-1) in cows abomasally infused with long-chain FA as free fatty acids or triglycerides forms, which was not observed for cholecystokininoctapeptide (CCK-8). However, in a recent study reported by Relling and Reynolds (2007), higher concentrations in plasma of GLP-1 and CCK-8 were shown in cows fed monounsaturated FA or PUFA as compared with cows fed saturated FA.…”

Effect of incremental amounts of camelina oil on milk fatty acid composition in lactating cows fed diets based on a mixture of grass and red clover silage and concentrates containing camelina expeller

“…Supplements of plant oils and oilseeds typically decrease DMI when included in amounts above 50 g of oil/kg of DM, a response often attributed to the adverse effect of unsaturated FA on rumen microbial communities, lowered ruminal OM and NDF digestion (Allen, 2000;Lock and Shingfield, 2004), and an increase in gut peptide secretion (Litherland et al, 2005;Relling and Reynolds, 2007). By design, incremental inclusion of CO in concentrate supplements increased the FA content of the total diet from 33 to 60 g/kg of DM.…”

Recent developments in altering the fatty acid composition of ruminant-derived foods

“…Compared Figure 4 Relationship between the amount of 18:2n-6 (K) or 18:3n-3 (J) infused at the abomasum and mammary secretion of 18:2n-6 and 18:3n-3 in lactating cows. Data derived from experiments involving infusions of examining the effects of post-ruminal infusion of soya oil (Litherland et al, 2005), soya fatty acids (Litherland et al, 2005;Ortiz-Gonzalez et al, 2007) and linseed oil (Petit et al, 2002;Kazama et al, 2010). Solid line indicates the relationship:-18:2n-6 milk 5 0.488 3 18:2n-6 infused 1 17.67 (n 5 11, R 2 5 0.968, P , 0.001) and the dotted line indicates the relationship:-18:3n-3 milk 5 0.499 3 18:3n-3 infused 1 3.55 (n 5 11, R 2 5 0.942, P , 0.001).…”