Effects of Low ω6:ω3 Ratio in Sow Diet and Seaweed Supplement in Piglet Diet on Performance, Colostrum and Milk Fatty Acid Profiles, and Oxidative Status.

Marcello Comi,Thi Xuan Nguyen,Valentino Bontempo,Richard Burchmore,Peter David Eckersall,Giovanni Savoini,Invernizzi Guido,Sara Panseri,Alessandro Agazzi,Helga Sauerwein

doi:10.3390/ani10112049

Abstract

Simple SummaryFeeding maternal animals divergent ratios of omega-6 (ω6) and omega-3 (ω3) fatty acids can change not only their health, physiological condition, and performance but also do the same for their offspring. In swine production, various ω6:ω3 ratios have been tested, but the search for an optimal proportion in the sow diet is still in progress. For piglets, weaning oxidative stress has been alleviated by supplementing with abundant sources of bioactive compounds. In this case, brown seaweed, a rich source of natural antimicrobials and antioxidants, can be a good candidate, but its supplementation in piglet diet is limited. This study explores the hypothesis that feeding a low ω6:ω3 ratio diet to sows during gestation and lactation, together with the supplementation of Ascophyllum nodosum for piglets during the post-weaning period, could benefit piglets’ performance and oxidative status more than the respective single treatment provided to the mother or the piglet. Results showed that the low dietary ω6:ω3 ratio (4:1) and seaweed supplement did not affect the post-weaning piglets’ growth rate and oxidative status. However, a low ω6:ω3 ratio diet alone improved weaning survival rate, suckling piglets’ weight gain, and total ω3 fatty acids in colostrum and milk.The ratio of omega-6 (ω6) to omega-3 (ω3) polyunsaturated fatty acids (PUFAs) in the diet contributes to animal health and performance modulations because they have mostly opposite physiological functions. Increasing ω3 PUFAs content in the maternal diet can stimulate antioxidative capacity in sow and piglets; however, the optimal ratio of ω6 and ω3 PUFAs in the sow diet is still under discussion. Rich sources of bioactive constituents such as brown seaweed are an excellent supplementation to promote animal health and antioxidant status. However, the knowledge of the effects of this compound, specifically in post-weaning piglets, is still limited. Moreover, the combined effect of a low ω6:ω3 PUFAs ratio in sow diet and seaweed supplementation in post-weaning piglets’ diet has never been studied. This research aims to assess the combined effect of a low ω6:ω3 ratio in sow diets and seaweed supplementation in piglet diets on their growth and oxidative status. We also assessed the impact of a low ω6:ω3 ratio in the maternal diet on reproduction, milk fatty acid (FA) profile, and plasma leptin concentration. Two sow diets (n = 8 each) contained either a control ratio (CR, 13:1 during gestation, starting from day 28 (G28) and 10:1 during lactation) or a low ratio (LR, 4:1 from G28 until the end of lactation (L-End)) of ω6:ω3 FA by adding soybean oil or linseed oil, respectively. Reproductive performance was evaluated. Colostrum and milk at lactation day 7 (L7) and L-End were collected to analyze FA profile. Plasma was collected at G28, G79, G108, L7, L14, and L-End for determination of leptin and oxidative status. At weaning, 20 male piglets were selected per sow group to form 4 diet treatments (n = 10 each), which were supplemented with or without 4 g/kg seaweed. Recording of growth performance and collection of blood were performed at days 0, 7, 15, and 21 of post-weaning for oxidative status. LR diet increased (p < 0.05) the survival rate of piglets at weaning, and individual and litter weight gains. Colostrum and milk at L7 and L-End had lower (p < 0.05) ω6:ω3 ratio in LR sows. Interaction between dietary treatments on sows and piglets was revealed for all examined growth parameters at most time points (p < 0.05). LR diet did not affect plasma leptin levels and oxidative status. These findings suggest that the seaweed supplement during post-weaning could not improve growth rate and oxidative status of piglets born from mothers receiving a low dietary ω6:ω3 ratio (4:1) during gestation and lactation. However, this low ratio was beneficial for weaning survival rate, sucking piglets’ weight gain, and ω3 enrichment in colostrum and milk.

Highlights

In pig production, there is a growing interest in lowering the ratio of omega-6 (ω6):omega-3 (ω3)polyunsaturated fatty acids (PUFAs) below 10:1 in maternal diets by using divergent sources of ω3PUFAs to promote the health and performance of sows and piglets [1,2,3,4,5].The enrichment of ω3 PUFAs in the diet has been shown to stimulate the antioxidative capacity in sow plasma and glutathione peroxidase activity (GSH-Px, an enzyme protecting cells against oxidative damage) in piglet liver, and decreased lipid peroxidation in piglet plasma [6]
We examined whether a low ω6:ω3 ratio (LR) in the sow diet and the supplementation of A. nodosum for piglets during the post-weaning period can benefit piglet performance and oxidative status more than the respective single treatment provided to the mother or the piglet
We found that a low ratio of ω6:ω3 PUFAs in the maternal diet tended to increase advanced oxidation products of proteins (AOPP) concentrations at the end of gestation, decreased the number of piglets born and piglets born alive, which could be explained by the involvement of AOPP

Summary

Introduction

There is a growing interest in lowering the ratio of omega-6 (ω6):omega-3 (ω3)polyunsaturated fatty acids (PUFAs) below 10:1 in maternal diets by using divergent sources of ω3PUFAs (e.g., fish oil, linseed oil) to promote the health and performance of sows and piglets [1,2,3,4,5].The enrichment of ω3 PUFAs in the diet has been shown to stimulate the antioxidative capacity in sow plasma and glutathione peroxidase activity (GSH-Px, an enzyme protecting cells against oxidative damage) in piglet liver, and decreased lipid peroxidation in piglet plasma [6]. PUFAs (e.g., fish oil, linseed oil) to promote the health and performance of sows and piglets [1,2,3,4,5]. A previous study found that increasing ω3 PUFAs in the maternal diet enhanced anti-inflammatory properties and reduced the pro-inflammatory effects of ω6 PUFAs, maintaining homeostasis [7]. A recent meta-analysis supports this notion in human studies [8], which showed that increasing the portion of ω3 PUFAs in the diet enhances the antioxidant defense mechanisms. There continues to be a debate about the optimal ratio of ω6 and ω3 PUFAs in the sow diet and how these effects can be transmitted from mother to offspring via milk, especially effects on piglets’ performance and oxidative status. Weaning is the most stressful event in life: the transition from a milk-based to a solid diet and changes in the environment and social relationships can reduce feed intake and conversion efficiency, disrupting gut mucosal barriers, and leading to reduced growth and health [9]

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