Manipulation Of Lactation Performance Of Sows By Steering The Dietary Energy Digestion And Metabolism

Feed is the driving force for the milk production of sows.The insufficient energy and nutrient ingestion of lactating sows cause worse lactation performance,excess body weight loss,and negative energy balance,which leads to progressive oxidative stress and compromises sow lactation performance and piglet growth.Starch,protein and fat,as the three main dietary energy sources of lactating female pigs,provide about 60%,25% and15% effective energy,respectively.Corn,soybean meal and oil are widely used as the main dietary energy sources for lactating pigs because they are rich in starch,protein and fat,respectively.Therefore,three experiments are included in this study.The intervention strategy is to promote dietary energy digestion and improve energy metabolism,and the sources and levels of dietary main nutrients(starch,protein and fat),the addition of digestible agents(complex digestive enzymes)and antioxidant substances(selenium and vitamin E)are used as intervention measures.Those experiments were aimed to explore the impacts and mechanism of the dietary energy digestion and metabolism intervention on lactating performance of sows by the digestibility,metabolism,antioxidant capacity,milk component,and milk production.Experiment 1 The sources and levels of dietary main nutrients interfere with the regulation of energy digestion on antioxidant capacity and lactation production performance of sowsExperiments 1-1 Regulation of dietary starch and protein source intervention on antioxidant and lactation performance of sowsThis experiment was aimed to replace starch contained in corn and protein contained in soybean meal with digestible starch source(pure corn starch)and protein source(fermented soybean meal)in the basal diet as intervention measures,respectively,to explore whether it can alleviate the negative balance of energy metabolism and oxidative stress by promoting energy digestion,so as to improve the lactation performance of sows.A total of twenty-four sows(Landrace × Yorkshire;parity 4)were assigned to 3 treatments(n = 8)with randomized complete block design from d 2 of lactation to d 28 of lactation.The treatments were: control(CON),fed with basal diet;corn starch(CS),20% pure CS substituted 60% CS provided by corn in CON;fermented soybean meal(FSM),8% FSM substituted 60% crude protein provided by soybean meal in CON.The initial litter size was11 piglets.The results were as follows: compared with CON,the CS and FSM numerically increased sow feed intake(P = 0.11),and further increased piglet body weight(P < 0.05)and average daily gain(P = 0.07);CS group increased the apparent total tract digestibility(ATTD)of dry matter(DM),gross energy(GE),and ash(P < 0.05),while decreased serum non-esterified fatty acids(NEFA)and β-hydroxybutyric acid(β-HBA)on d 28 and serum aspartate aminotransferase(AST),alanine aminotransferase(ALT),glutathione peroxidase(GSH-Px),and total antioxidant capacity(T-AOC)on d 14(P < 0.10),decreased serum superoxide dismutase(SOD)on d 14 and 28(P < 0.05),but increased milk supernatant SOD on d 28(P < 0.05);the FSM group increased the ATTD of ash,serum GSH-Px on d14 and milk supernatant GSH-Px on d 28(P < 0.05).The results show that CS or FSM diets can increase feed intake and nutrient digestibility of sows,and promote the growth of piglets.The CS diet can reduce body mobilization and enhance liver health of sows.The FSM diet can improve the antioxidant capacity of sows.Experiment 1-2 Regulation of dietary fat level and source intervention on lactation performance of sowsBased on the clear regulation effects of digestible starch source and protein source on antioxidant and milk production performance of lactating female pigs in trial 1-1,this experiment was conducted to investigate the regulation of dietary fat level and source intervention on milk production performance of lactating female pigs.A total of 40second-parity sows(Danish Landrace × Yorkshire)were assigned to 1 of 5 dietary treatments(n = 8)from d 108 of gestation to d 28 of lactation: low fat control,a diet containing 3% added animal fat;or one of 4 fat-rich diets with 8% added fat: coconut oil(CO),fish oil(FO),sunflower oil(SO),or 4% octanoic acid plus 4% FO.The initial litter size was 12 piglets by cross-foster postpartum.The results were as follows: compared with low fat group,high fat group increased daily dietary fatty acid and carbon intake(P < 0.05),and hence resulted in higher daily milk fat(P = 0.05)and energy output(P = 0.10).However,there were no differences in daily feed intake,milk yield,and litter weight gain of piglets no matter between fat levels or sources(P > 0.05).Experiment 2 Effects of dietary antioxidant substances(selenium and vitamin E)on energy metabolism on antioxidant and lactation performance of sowsBased on the clear regulation effect of energy digestion by the sources and levels of three major dietary nutrients on antioxidant and lactation performance of sows in experiment 1,the purpose of this experiment was to explore the effects of energy metabolism with antioxidant substances(selenium and vitamin E)intervention on antioxidant and lactation performance of sows.A total of 36 primiparous sows(DLY)were randomly assigned to 4 treatments(n = 9)from d 2 to 21 of lactation.This study was conducted in a 2 × 2 factorial design,with sodium selenite(SS)and2-hydroxy-4-methylselenobutanoic acid(HMSe BA)as Se sources to provide 0.30 mg/kg Se,and VE levels were 50 or 150 mg/kg.The initial litter size was 10 piglets.The results were as follows:(1)compared with SS,sows fed HMSe BA improved litter average daily weight gain on d 15-21(P < 0.10)and d 2-21 and milk yield on d 21(P < 0.05),while decreased serum ALT on d 11 and milk SCC on d 21(P < 0.10).In milk supernatant,HMSe BA increased SOD,CAT,and GSH-Px on d 11(P < 0.10),but decreased MDA and IL-1β on d 11(P < 0.05)and IFN-γ on d 11 and 21(P < 0.10);(2)sows fed elevating VE increased SOD on d 21 and serum GSH-Px on d 11 and 21 in milk supernatant(P < 0.05);(3)The interaction of selenium sources and VE levels impacted piglet body weight on d 14(P = 0.08),showing positive effect when HMSe BA combination with higher VE on piglet body weight on d 14.The results showed that HMSe BA had better effects on antioxidant capacity,milk yield,milk quality and growth of piglets than SS.The e effect of high VE level on antioxidant capacity of sows and growth of piglets depends on selenium source and has positive effect when combined with HMSe BA.Experiment 3 Effects of combined intervention of dietary energy digestion and metabolism on antioxidant and lactation performance of sowsThe above experiments indicated that the intervention of energy digestion with digestible nutrient sources or the addition of antioxidant substances to interfere with energy metabolism is beneficial to reduce oxidative stress and improve lactation performance of sows,this study further explored the regulation of antioxidant and lactation performance of lactating sows through the combined application of complex digestive enzyme intervention in energy digestion and the intervention of energy metabolism with antioxidant substances.A total of 50 primiparous sows(DLY)were randomly assigned to 5 treatments(n = 10)from d 2 to 21 of lactation: control(CON);high quality(HQ)with greater energy density(200 kcal/kg higher net energy than NC);or the CON diet supplemented with 500 mg/kg flavor and 100 mg/kg multi-enzymes(F+E);organic plus VE(OS+VE),based on CON group,the SS was replaced by HMSe BA and extra added 100 mg/kg VE;comprehensive application group(CG),dietary inclusion of 500 g/t flavor,100 g/t multi-enzymes and 100mg/kg VE,and HMSe BA was used to replaced SS based on CON group.The initial litter size was 9 piglets.The results were as follows: compared with the CON diet,OS+VE and CG diet increased feed intake of sow(P < 0.05);other groups decreased serum AST(P <0.05),increased serum SOD and piglet body weight and daily weight gain(P < 0.05);F+E diet increased the ATTD of ash,crude fiber,neutral detergent fiber and P(P < 0.05);HQ and CG diets increased the ATTD of DM,ether extract,GE,crude protein,ash,neutral detergent fiber,acid detergent fiber,crude fiber and P(P < 0.05);OS+VE diet increased the ATTD of DM,ash,neutral detergent fiber and P and the ingestion of digestibility energy(P < 0.10);CG diet decreased serum malondialdehyde(P = 0.08);F+E,OS+VE,and CG diet increased catalase and total-antioxidant capacity(P < 0.05)but decreased malondialdehyde in milk supernatant(P < 0.05).Compared with CON and HQ,the OS+VE and CG diet increased GSH-Px activity in milk supernatant(P < 0.05).This experiment showed that different energy digestion and metabolism interventions were beneficial to improve antioxidant and milk production performance of sows.Overall,this study indicated that:(1)dietary inclusion of 20% of cornstarch or 8% of FSM,or dietary supplementation of multi-enzymes can increase sows’ feed intake,energy digestibility,or antioxidant capacity,which lead to better lactation performance;(2)fat level in sow diet increased from 3% to 8% or high fat diet included SO and CO increased milk fat content,but there were no differences in milk yield;(3)the elevating VE was dependent on HMSe BA to improve sow antioxidant capacity,thereby increasing antioxidant capacity and lactation performance of sow;(4)low nutrient diet(net energy decreased by 200 kcal)inclusion of multi-enzymes and antioxidant(HMSe BA and VE)can maintain sows’ antioxidant capacity and lactation performance.This study provided data support for the development of effective nutrition strategies to reduce feed resource shortage and provide theoretical basis for the establishment of nutrition regulation techniques to improve the lactation performance of sows.