Medium-chain fatty acids and monoglycerides as feed additives for pig production:towards gut health improvement and feed pathogen mitigation

Ongoing challenges in the swine industry,such as reduced access to antibiotics and virus outbreaks(e.g.,porcine epidemic diarrhea virus,African swine fever virus),have prompted calls for innovative feed additives to support pig production.Medium-chain fatty acids(MCFAs)and monoglycerides have emerged as a potential option due to key molecular features and versatile functions,including inhibitory activity against viral and bacterial pathogens.In this review,we summarize recent studies examining the potential of MCFAs and monoglycerides as feed additives to improve pig gut health and to mitigate feed pathogens.The molecular properties and biological functions of MCFAs and monoglycerides are first introduced along with an overview of intervention needs at different stages of pig production.The latest progress in testing MCFAs and monoglycerides as feed additives in pig diets is then presented,and their effects on a wide range of production issues,such as growth performance,pathogenic infections,and gut health,are covered.The utilization of MCFAs and monoglycerides together with other feed additives such as organic acids and probiotics is also described,along with advances in molecular encapsulation and delivery strategies.Finally,we discuss how MCFAs and monoglycerides demonstrate potential for feed pathogen mitigation to curb disease transmission.Looking forward,we envision that MCFAs and monoglycerides may become an important class of feed additives in pig production for gut health improvement and feed pathogen mitigation.

Growth performance,oxidative stress and immune status of newly weaned pigs fed peroxidized lipids with or without supplemental vitamin E or polyphenols

Background:This study evaluated the use of dietary vitamin E and polyphenols on growth,immune and oxidative status of weaned pigs fed peroxidized lipids.A total of 192 piglets(21 days of age and body weight of 6.62±1.04 kg)were assigned within sex and weight blocks to a 2×3 factorial arrangement using 48 pens with 4 pigs per pen.Dietary treatments consisted of lipid peroxidation(6%edible soybean oil or 6%peroxidized soybean oil),and antioxidant supplementation(control diet containing 33 IU/kg DL-α-tocopheryl-acetate;control with 200 IU/kg additional dl-α-tocopheryl-acetate;or control with 400 mg/kg polyphenols).Pigs were fed in 2 phases for 14 and 21 days,respectively.Results:Peroxidation of oil for 12 days at 80°C with exposure to 50 L/min of air substantially increased peroxide values,anisidine value,hexanal,and 2,4-decadienal concentrations.Feeding peroxidized lipids decreased(P<0.001)body weight(23.16 vs.18.74 kg),daily gain(473 vs.346 g/d),daily feed intake(658 vs.535 g/d)and gain:feed ratio(719 vs.647 g/kg).Lipid peroxidation decreased serum vitamin E(P<0.001)and this decrease was larger on day 35(1.82 vs.0.81 mg/kg)than day 14(1.95 vs.1.38 mg/kg).Supplemental vitamin E,but not polyphenols,increased(P≤0.002)serum vitamin E by 84%and 22%for control and peroxidized diets,respectively(interaction,P=0.001).Serum malondialdehyde decreased(P<0.001)with peroxidation on day 14,but not day 35 and protein carbonyl increased(P<0.001)with peroxidation on day 35,but not day 14.Serum 8-hydroxydeoxyguanosine was not affected(P>0.05).Total antioxidant capacity decreased with peroxidation(P<0.001)and increased with vitamin E(P=0.065)and polyphenols(P=0.046)for the control oil diet only.Serum cytokine concentrations increased with feeding peroxidized lipids on day 35,but were not affected by antioxidant supplementation(P>0.05).Conclusion:Feeding peroxidized lipids negatively impacted growth performance and antioxidant capacity of nursery pigs.Supplementation of vitamin E and polyphenols improved total antioxidant capacity,especially in pigs fed control diets,but did not restore growth performance.

Sow performance in response to natural betaine fed during lactation and post-weaning during summer and non-summer months

Background: Two studies were conducted to evaluate the effects of dietary natural betaine on sow reproductive performance during summer(Exp. 1) and non-summer months(Exp. 2). Treatments were designed as a 2 × 2 factorial arrangement with factors including dietary betaine(0 or 0.2%) and period of supplementation(lactation or post-weaning until 35 days post-insemination). In Exp. 1, 322 and 327 sows and in Exp. 2, 300 and 327 sows representing young(parity 1 and 2) and mature(parity 3 to 6) sows, respectively, were used.Results: In Exp. 1, supplementation of betaine during lactation increased sow body weight losses(-11.95 vs.-14.63 kg;P = 0.024), reduced feed intake(4.12 vs. 4.28 kg/d;P = 0.052), and tended to reduce percentage of no-value pigs(P = 0.071). Betaine fed post-weaning reduced weaning-to-estrus interval(5.75 vs. 6.68 days;P = 0.054) and farrowing rate(86.74% vs. 91.36%;P = 0.060), regardless of parity group. Post-hoc analysis with sows clustered into 3 parity groups(1, 2 and 3, and 4+) indicated that betaine fed in lactation to parity 4+ sows(P = 0.026) and betaine fed post-weaning to parity 1 sows increased the number of pigs born in the subsequent cycle(P ≤ 0.05). In Exp. 2, betaine fed during lactation tended to reduce the weaning-to-estrus interval(6.64 vs. 7.50 days;P = 0.077) and farrowing rate(88.23% vs.83.54%;P = 0.089), regardless of parity group. Feeding betaine post-weaning reduced number of pigs born(13.00 vs.13.64;P = 0.04) and pigs born alive(12.30 vs. 12.82;P = 0.075), regardless of parity group.Conclusions: Using 0.2% betaine during the non-summer months did not benefit sow performance. During the summer, betaine supplementation in lactation increased subsequent litter size in parity 4+ sows. Betaine fed during the post-weaning period reduced the wean-to-estrus interval and farrowing rate, increased total number of pigs born for parity 1 sows and reduced total number of pigs born to parity 4+ sows. Further research is needed to determine if the detrimental effects on feed intake and farrowing rate may be correlated and depend on dietary betaine level.

Optimizing dietary lipid use to improve essential fatty acid status and reproductive performance of the modern lactating sow:a review

Dietary lipid supplementation benefits the prolific and high-producing modern lactating sow. A comprehensive review of recent studies showed that lipid supplementation increases average daily energy intake, which is partitioned for lactation as indicated by greater milk fat output and improved litter growth rate. Recent compelling findings showed that addition of particular lipids during lactation improved the subsequent reproductive outcome of sows. Such benefits were related to the level of dietary essential fatty acids（EFA, linoleic acid, C18：2n-6; and α-linolenic acid, C18：3n-3） during lactation. Lactation diets without supplemental EFA resulted in a pronounced negative balance（intake minus milk output） of linoleic（-25.49 g/d） and α-linolenic acid（-2.75 g/d）; which compromised sow fertility（farrowing rate 〈 75 % and culling rates 〉 25 % of weaned sows）. This phenomenon seems to be increasingly important with advancing sow age because of a progressive reduction of body EFA pool over successive lactations. The net effect of supplemental EFA during lactation was to create a positive EFA balance, which improved the subsequent reproduction of sows. Adequate linoleic acid intake improved the proportion of sows that farrowed in the subsequent cycle（Farrowing rate（%） = [（-1.5 × 10^-3× linoleic acid intake（g/d）^2） ＋（0.53 × linoleic acid intake（g/d）） ＋（45.2）]; quadratic P = 0.002, R^2= 0.997, RMSE = 0.031）. In addition, increasing linoleic acid intake increased the number of pigs born in the subsequent cycle（total pigs born（n） = [（9.4 × 10^-5× linoleic acid intake（g/d）^2） ＋（0.04 × linoleic acid intake（g/d）） ＋（10.94）]; quadratic P = 0.002, R^2= 0.997, RMSE = 0.031）. Supplemental α-linolenic acid resulted in a rapid return to estrus（sows bred： sows weaned = 94.2 %; wean-to-estrus interval = 4.0 d） and achieved a high retention of pregnancy（sows pregnant： sows bred = 98 %）. Collectively, we conclude that a minimum dietary intake of10 g/d of α-linolenic acid, simultaneous with a minimum of 125 g/d of linoleic acid should be provided to ≥ 95 % of the sows; thereby, achieving a maximum sow reproductive efficiency through multiple mechanisms that include rapid return to estrus, high maintenance of pregnancy and large subsequent litter size in mature sows, that appear to be susceptible to EFA deficiency.