Optimal dietary copper requirements and relative bioavailability for weanling pigs fed either copper proteinate or tribasic copper chloride

Background: The objective of this study was to determine the effects of supplementing Cu on growth performance, Cu metabolism and Cu-related enzyme activities of weanling pigs fed diets with two different Cu sources, and to estimate optimal Cu requirements and relative bioavailability from these two sources for pigs.Methods: Weanling pigs were allocated to 14 treatments arranged factorially, including 6 added Cu levels(5, 10,20, 40, 80, 160 mg/kg), and 2 mineral sources(tribasic Cu chloride, TBCC and copper proteinate, Cu Pro), as well as one negative control(0 mg/kg added Cu level) and one maximum allowed level treatment(200 mg/kg TBCC) for the entire 38-d experiment. Growth performance, mineral status and enzyme activities were measured at the end of this study.Results: Increasing levels of Cu showed linear and quadratic responses(P < 0.01) for final BW, ADG and FCR regardless of the sources. Supplementation with TBCC(> 80 mg/kg) and Cu Pro(> 20 mg/kg) significantly decreased(P < 0.05) diarrhea incidence of weanling pigs. There were linear and quadratic increases(P < 0.01) in bile, hepatic,and intestinal Cu concentrations, fecal Cu contents, and plasma enzyme activities(alkaline phosphatase,ceruloplasmin, Cu, Zn-Superoxide dismutase(Cu/Zn SOD), and glutathione peroxidase), whereas plasma malondialdehyde decreased(P < 0.01) linearly and quadratically as dietary Cu level increased. Similarly, pigs fed Cu Pro absorbed and retained more Cu and excreted less Cu than those fed TBCC when supplemented 80 mg/kg and above. Optimal dietary Cu requirements for pigs from 28 to 66 d of age estimated based on fitted broken-line models(P < 0.05) of bile Cu, plasma Cu/Zn SOD and growth performance were 93–140 mg/kg from TBCC, and 63–98 mg/kg from Cu Pro accordingly. According to slope ratios from multiple linear regression, the bioavailability value of Cu Pro relative to TBCC(100%) was 156–263%(P < 0.01).Conclusion: The findings indicated that Cu recommendation from current NRC(5–6 mg/kg) was not sufficient to meet the high requirement of weanling pigs. Cu from Cu Pro was significantly more bioavailable to weanling pigs than TBCC in stimulating growth and enzyme activities, decreasing diarrhea frequency and fecal Cu contents to the environment.

Resveratrol compares with melatonin in improving in vitro porcine oocyte maturation under heat stress

Background： Resveratrol, an important phyto-antioxidant commonly found in grapes, mulberry, and other plants,has a variety of functions including anti-aging, anti-cancer and anti-inflammatory activities. In the current study, we investigated the beneficial effects of resveratrol on in vitro porcine oocyte maturation under heat stress（HS）. The effect of resveratrol, melatonin and their combination on alleviating HS was compared according to the maturation rate of oocytes and the development competence of embryos after parthenogenetic activation（PA）.Results： Supplementation with resveratrol（2.0 μmol/L） not only improved the nuclear maturation but also raised the blastocyst rate of porcine embryos＇ PA from oocytes that underwent HS by increasing their glutathione（GSH）level, reducing reactive oxygen species（ROS） and up-regulating the expression of Sirtuin 1（SIRT1）. It was also found that melatonin（10^-7mol/L） and the combination of resveratrol（2.0 μmol/L） plus melatonin（10^-7mol/L） exhibited more potent effects than resveratrol alone regarding their protective activities on oocyte maturation under HS.Conclusions： This study compared the efficiencies of resveratrol, melatonin and their combination for protecting porcine oocytes from heat stress. The mechanisms are attributed to the fact that each treatment may have different ability to regulate the synthesis of steroid hormones and the expression of mature related genes.

Clostridium species as probiotics:potentials and challenges

Clostridium species,as a predominant cluster of commensal bacteria in our gut,exert lots of salutary effects on our intestinal homeostasis.Up to now,Clostridium species have been reported to attenuate inflammation and allergic diseases effectively owing to their distinctive biological activities.Their cellular components and metabolites,like butyrate,secondary bile acids and indolepropionic acid,play a probiotic role primarily through energizing intestinal epithelial cells,strengthening intestinal barrier and interacting with immune system.In turn,our diets and physical state of body can shape unique pattern of Clostridium species in gut.In view of their salutary performances,Clostridium species have a huge potential as probiotics.However,there are still some nonnegligible risks and challenges in approaching application of them.Given this,this review summarized the researches involved in benefits and potential risks of Clostridium species to our health,in order to develop Clostridium species as novel probiotics for human health and animal production.

Recent advances in immunoassays and biosensors for mycotoxins detection in feedstuffs and foods

Mycotoxins are secondary metabolites produced by fungus.Many mycotoxin species are highly toxic and are frequently found in cereals and feedstuffs.So,powerful detection methods are vital and effective ways to prevent feed contamination.Traditional detection methods can no longer meet the needs of massive,real-time,simple,and fast mycotoxin monitoring.Rapid detection methods based on advanced material and sensor technology are the future trend.In this review,we highlight recent progress of mycotoxin rapid detection strategies in feedstuffs and foods,especially for simultaneous multiplex mycotoxin determination.Immunoassays,biosensors,and the prominent roles of nanomaterials are introduced.The principles of different types of recognition and signal transduction are explained,and the merits and pitfalls of these methods are compared.Furthermore,limitations and challenges of existing rapid sensing strategies and perspectives of future research are discussed.

Different copper sources and levels affect growth performance,copper content,carcass characteristics,intestinal microorganism and metabolism of finishing pigs

Copper(Cu)is an essential trace element in the production of swine.This study was conducted to investigate the effect of 3 different sources of Cu on growth performance,Cu metabolism,and intestinal microorganisms of finishing pigs,so as to estimate the bioavailability of the 3 sources for pigs.A total of 42 male finishing pigs(88.74±5.74 kg)were randomly allocated to 7 treatments.The factors were 3 sources(CuSO4,Cu-glycine,Cu-proteinate)and 2 levels(5 and 20 mg/kg)of Cu,plus one negative control treatment(0 mg/kg added Cu level)for the entire 28-d experiment.The average daily gain(ADG)and feed to gain ratio(F:G)both increased when Cu was added.The Cu level in liver,bile,kidney,serum,lung,urine and feces rose(P<0.001)with increasing dietary Cu level regardless of the source.Meanwhile,pigs receiving organic Cu(glycinate or proteinate)retained more Cu and excreted less Cu than those receiving inorganic Cu(CuSO4),which showed that organic forms were more bioavailable.At the transcriptional level,changes in the level and source of dietary Cu resulted in modulation of transporters.In the jejunal mucosa,import transporter high affinity copper uptake protein 1(CTR1)and export transporter ATPase copper transporting alpha(ATP7A)in supplemental Cu treatments were down-regulated compared to the control.Also,peptide transporter 1(PepT1)and lanine-serine-cysteine transporter,type-2(ASCT2)were significantly(P<0.01)up-regulated in 20 mg/kg Cu-proteinate and Cu-glycinate treatments,respectively.Microbial diversity was lowest in the 20 mg/kg CuSO4 treatment,and the ratio of Firmicutes to Bacteroidetes was higher in added Cu treatments,especially Cu-glycinate treatment.These results indicate that uptake of different Cu forms is facilitated by different transporters and transport mechanisms,and compared with inorganic Cu,organic Cu provides benefits to intestinal microflora and reduces Cu excretion.