Pyrroloquinoline quinone regulates the redox status in vitro and in vivo of weaned pigs via the Nrf2/HO-1 pathway

Background:Oxidative stress is a main cause of piglet gut damage and diarrhea.Pyrroloquinoline quinone(PQQ),is a novel redox cofactor with antioxidant properties.However,the effect and mechanism that PQQ supplementation decreases oxidative injury in weaned pigs is not understood.Therefore,the aim of this study is to confirm the effect of PQQ on regulating redox status in weaned pigs and the mechanism for antioxidant function by porcine intestinal epithelial cell line(IPEC-J2)challenged with H_(2)O_(2).Results:Experiment 1,144 Duroc×Landrace×Yorkshire pigs(weaned at 28 d)were allocated to four groups:received a basal diet(control)and diets supplemented with 0.15%,0.30%and 0.45%PQQ,respectively.On d 28,growth performance,diarrhea incidence and redox factors were measured.Experiment 2,IPEC-J2 were treated with or without PQQ in the presence or absence of H_(2)O_(2)for indicated time points.Experiment 3,IPEC-J2 were transfected with or without Nrf2 siRNA,then treated according to Experiment 2.The cell viability,redox factors,protein of tight junctions and Nrf2 pathway were determined.In vivo,PQQ supplementation demonstrated dose-related improvements in average daily gain,and gain to feed ratio(Linear P<0.05).During d 0–28,compared to controls,0.45%PQQ supplementation for pigs decreased diarrhea incidence and MDA content in liver and jejunum,and increased concentration of SOD in liver;0.3%PQQ supplementation decreased ileal and liver MDA concentration;and 0.15%PQQ supplementation decreased ileal MDA concentration(P<0.05).In vitro,compared to cells cultured with H_(2)O_(2),pre-treatment with PQQ increased cell viability,tight junction proteins expression including ZO-1,ZO-2,Occludin and Claudin-1;and decreased ROS concentration and level of Caspase-3(P<0.05);as well as upregulated the ratio of Bcl-2 to Bax and protein expression of nuclear Nrf2,HO-1.Notably,Nrf2 knockdown by transfection with Nrf2 siRNA largely abrogated the positive effects of PQQ pretreatment on H_(2)O_(2)-induced intracellular changes.Conclusions:PQQ administration attenuated oxidative stress in weaned pigs which is associated with activation of Nrf2/HO-1 pathway.

Effects of Reduced Nocturnal Temperature on Performance and Behavior of Nursery Pigs

Previous studies suggested that pigs prefer lower environmental temperatures during nighttime compared to daytime. So reducing nocturnal temperature in nursery barns may not jeopardize performance or welfare of pigs, but can save energy for heating the barn. A study was conducted to investigate growth performance and behavioral response of nursery pigs to reduced nocturnal temperature. This study was conducted in four replicates, each utilizing 270 newly weaned pigs and lasting for 5 wk. Temperature setpoint in the control room （CON） was started at 30℃ and decreased by 2℃ per week. In the treatment room （RNT）, temperature setpoint was maintained same as in CON between 7：00 h and 19：00 h, and reduced by 8~C between 19：00 h and 7：00 h starting from d 5. Growth performance （15 pens/room, 9 pigs/pen, BW=（6.3±0.61） kg） was monitored for 5 wk, and behaviors in 6 pens in each room were video-recorded for 24 h 3 d after being exposed to the experimental temperature. Instantaneous scan sampling was performed to determine time budgets for standing, sitting, eating, drinking, belly nosing, three postures of lying, and huddling. Two focal pigs were continuously viewed to record duration and occurrence of eating and drinking. Reduced nocturnal temperature did not affect the growth performance of the pigs, time spent standing, sitting, total lying and eating or duration and frequencies of eating and drinking （all P〉0.10）. However, RNT increased time spent lying sternal （83 vs. 72%, P〈0.001） and number of pigs that were huddling （70 vs. 50% of lying pigs, P〈0.001）, and decreased time spent lying laterally （0.8 vs. 4.6%, P〈0.001）, lying half laterally （5.3 vs. 11.0%, P〈0.001）, and belly nosing （0.9 vs. 1.7%, P=0.01） during nighttime. These results indicate that nursery pigs adopted the posture of lying sternal and huddled together to reduce heat loss from their body surface to maintain thermal balance and growth performance in RNT. Such mild reduction in nocturnal temperature in the nursery barn can save energy for heating the barn without negative effects on performance and behavior of nursery pigs.

A systematic review and meta-analysis of dietary fat effects on reproductive performance of sows and growth performance of piglets

Effects of added fat in sow diets on the sows’reproductive performance and offspring growth performance are influenced by multiple factors such as genetics,nutrition,parity,ambient temperatures,and farm management.Individual studies cannot cover all these factors.With the view to address this challenge,we searched all studies that were published from 1986 to 2020,and performed a systematic review and meta-analysis on the fat effect.In total,19 papers were collected and analyzed.Fat supplementation in sow diets during late gestation and lactation decreased average daily feed intake(ADFI,P<0.05)and tended to increase average daily energy intake(ADEI,P=0.11).It had no impact on litter weights at birth(P=0.40)or weaning(P=0.46).It increased total numbers of piglets at birth(P=0.07),but had no effect on liveborn per litter(P=0.90)or survival rate(P=0.48)of piglets to weaning.Fat supplementation had no significant effect on sow body weight loss(P=0.67)or backfat thickness changes(P=0.66),but sows fed diets with added fat had increased milk fat concentration(P=0.03)and shorter wean to estrus intervals(WEI,P=0.01).In specific circumstances,fat supplementation tended to improve growth performance of piglets with low litter weights at birth(P=0.14),or when the sows lost large amounts of body weight during lactation(P=0.11).The level of supplemented fat was 10%and higher would decrease liveborn per litter at neutral temperature(P=0.10).The meta-analysis revealed that fat supplementation to sows diet during late gestation and lactation can be beneficial for sow reproductive performance and litter growth performance.

Addition of tert-butylhydroquinone(TBHQ)to maize oil reduces lipid oxidation but does not prevent reductions in serum vitamin E in nursery pigs

Background: Maize oil is abundantly used in foods and feeds and is highly susceptible to oxidation. Consequently,commercially available antioxidants should be evaluated for effectiveness against lipid oxidation in swine diets. Our study was conducted to evaluate growth performance of nursery pigs fed oxidized maize oil and to determine effects of using antioxidants on oxidative status in a 2 × 2 factorial design. Two hundred eight weaned pigs were blocked by initial BW into 13 blocks, resulting in 4 pigs per pen and 13 pens per treatment. Dietary treatments included 6% unoxidized or oxidized maize oil, and 0 or 60 mg/kg of tert-butylhydroquinone(TBHQ), which was added after lipid oxidation. Data for growth performance were collected from 5 time periods of a two-phase feeding program(Phase 1 = d 0 to 12 and Phase 2 = d 13 to 34). Serum and liver samples were collected from one pig per pen, which had initial BW closest to average BW to determine oxidative status on d 34.Results: Oxidized maize oil was heated for 12 h at 185 °C with 12 L/min of air, yielding a peroxide value(PV) of 5.98 m Eq O2/kg and TBARS of 0.11 mg MDA eq/g. Addition of TBHQ to diets containing oxidized maize oil decreased PV by 37% and increased the oil stability index by 69%. Final BW, ADG, ADFI, and G:F of pigs were not different among the four dietary treatments. However, pigs fed oxidized maize oil tended(P < 0.08) to increase hepatosomatic index by 5% compared with those fed unoxidized oil, and this was not affected by adding TBHQ.The serum vitamin E concentration of pigs fed oxidized maize oil was less(P < 0.03) than pigs fed unoxidized oil,but this reduction was not reversed by adding TBHQ. Finally, the serum and liver selenium concentration were not different among the treatments.Conclusions: The addition of TBHQ did not affect growth performance and vitamin E status in pigs fed moderately oxidized maize oil, but TBHQ reduced lipid oxidation, enhanced the oil stability, and appeared to reduce oxidative stress.