Journal of Animal Science and Biotechnology最新文献

Background: Heat stress has severe negative consequences on performance and health of pigs, leading to significant economic losses. The objective of this study was to investigate the effects of supplemental vitamin E and a botanical extract in feed or drinking water on growth performance, intestinal health, and oxidative and immune status in growing pigs housed under heat stress conditions.

Methods: Duplicate experiments were conducted, each using 64 crossbred pigs with an initial body weight of 50.7 ± 3.8 and 43.9 ± 3.6 kg and age of 13-week and 12-week, respectively. Pigs (n = 128) were housed individually and assigned within weight blocks and sex to a 2 × 4 factorial arrangement consisting of 2 environments (thermo-neutral (21.2 °C) or heat-stressed (30.9 °C)) and 4 supplementation treatments (control diet; control + 100 IU/L of D-α-tocopherol in water; control + 200 IU/kg of DL-α-tocopheryl-acetate in feed; or control + 400 mg/kg of a botanical extract in feed).

Results: Heat stress for 28 d reduced (P ≤ 0.001) final body weight, average daily gain, and average daily feed intake (-7.4 kg, -26.7%, and -25.4%, respectively) but no effects of supplementation were detected (P > 0.05). Serum vitamin E increased (P < 0.001) with vitamin E supplementation in water and in feed (1.64 vs. 3.59 and 1.64 vs. 3.24), but not for the botanical extract (1.64 vs. 1.67 mg/kg) and was greater when supplemented in water vs. feed (P = 0.002). Liver vitamin E increased (P < 0.001) with vitamin E supplementations in water (3.9 vs. 31.8) and feed (3.9 vs. 18.0), but not with the botanical extract (3.9 vs. 4.9 mg/kg). Serum malondialdehyde was reduced with heat stress on d 2, but increased on d 28 (interaction, P < 0.001), and was greater (P < 0.05) for antioxidant supplementation compared to control. Cellular proliferation was reduced (P = 0.037) in the jejunum under heat stress, but increased in the ileum when vitamin E was supplemented in feed and water under heat stress (interaction, P = 0.04). Tumor necrosis factor-α in jejunum and ileum mucosa decreased by heat stress (P < 0.05) and was reduced by vitamin E supplementations under heat stress (interaction, P < 0.001).

Conclusions: The addition of the antioxidants in feed or in drinking water did not alleviate the negative impact of heat stress on feed intake and growth rate of growing pigs.

Background: Transmissible gastroenteritis virus (TGEV) is one of the main pathogens causing severe diarrhea of piglets. The pathogenesis of TGEV is closely related to intestinal inflammation. All-trans retinoic acid (ATRA) is the main active metabolite of vitamin A, which has immunomodulatory and anti-inflammatory properties. However, it is unclear whether ATRA can alleviate TGEV-induced intestinal inflammation and barrier dysfunction in piglets. This study aimed to investigate the effects of ATRA on growth performance, diarrhea, intestinal inflammation and intestinal barrier integrity of TGEV-challenged piglets.

Methods: In a 19-d study, 32 weaned piglets were randomly divided into 4 treatments: Control group (basal diet), TGEV group (basal diet + TGEV challenge), TGEV + ATRA5 group (basal diet + 5 mg/d ATRA + TGEV challenge) and TGEV + ATRA15 group (basal diet + 15 mg/d ATRA + TGEV challenge). On d 14, piglets were orally administered TGEV or the sterile medium.

Results: Feeding piglets with 5 and 15 mg/d ATRA alleviated the growth inhibition and diarrhea induced by TGEV (P < 0.05). Feeding piglets with 5 and 15 mg/d ATRA also inhibited the increase of serum diamine oxidase (DAO) activity and the decrease of occludin and claudin-1 protein levels in jejunal mucosa induced by TGEV, and maintained intestinal barrier integrity (P < 0.05). Meanwhile, 5 mg/d ATRA feeding increased the sucrase activity and the expressions of nutrient transporter related genes (GLUT2 and SLC7A1) in jejunal mucosa of TGEV-challenged piglets (P < 0.05). Furthermore, 5 mg/d ATRA feeding attenuated TGEV-induced intestinal inflammatory response by inhibiting the release of interleukin (IL)-1β, IL-8 and tumor necrosis factor-α (TNF-α), and promoting the secretion of IL-10 and secretory immunoglobulin A (sIgA) (P < 0.05). Feeding 5 mg/d ATRA also down-regulated the expressions of Toll-like receptors and RIG-I like receptors signaling pathway related genes (TLR3, TLR4, RIG-I, MyD88, TRIF and MAVS) and the phosphorylation level of nuclear factor-κB-p65 (NF-κB p65), and up-regulated the inhibitor kappa B alpha (IκBα) protein level in jejunal mucosa of TGEV-challenged piglets (P < 0.05).

Conclusions: ATRA alleviated TGEV-induced intestinal barrier damage by inhibiting inflammatory response, thus improving the growth performance and inhibiting diarrhea of piglets. The mechanism was associated with the inhibition of NF-κB signaling pathway mediated by TLR3, TLR4 and RIG-I.

Background: Despite their low abundance in sperm, mitochondria have diverse functions in this cell type, including energy production, signalling and calcium regulation. In humans, sperm mitochondrial DNA content (mtDNAc) has been reported to be negatively linked to sperm function and fertility. Yet, the association between mtDNAc and sperm function in livestock remains unexplored. For this reason, this study aimed to shed some light on the link between mtDNAc and sperm function and fertilising potential in pigs. A qPCR method for mtDNAc quantification was optimised for pig sperm, and the association of this parameter with sperm motility, kinematics, mitochondrial activity, and fertility was subsequently interrogated.

Results: First, the qPCR method was found to be sensitive and efficient for mtDNAc quantification in pig sperm. By using this technique, mtDNAc was observed to be associated to sperm motility, mitochondrial activity and in vivo, but not in vitro, fertility outcomes. Specifically, sperm with low mtDNAc were seen to exhibit greater motility but decreased mitochondrial activity and intracellular reactive oxygen species. Interestingly, samples with lower mtDNAc showed higher conception and farrowing rates, but similar in vitro fertilisation rates and embryo development, when compared to those with greater mtDNAc.

Conclusions: These findings enrich our comprehension of the association of mtDNAc with sperm biology, and lay the foundation for future research into employing this parameter as a molecular predictor for sperm function and fertility in livestock.

Background: Our previous studies demonstrated that divalent organic iron (Fe) proteinate sources with higher complexation or chelation strengths as expressed by the greater quotient of formation (Q_f) values displayed higher Fe bioavailabilities for broilers. Sodium iron ethylenediaminetetraacetate (NaFeEDTA) is a trivalent organic Fe source with the strongest chelating ligand EDTA. However, the bioavailability of Fe when administered as NaFeEDTA in broilers and other agricultural animals remains untested. Herein, the chemical characteristics of 12 NaFeEDTA products were determined. Of these, one feed grade NaFeEDTA (Q_f = 2.07 × 10⁸), one food grade NaFeEDTA (Q_f = 3.31 × 10⁸), and one Fe proteinate with an extremely strong chelation strength (Fe-Prot ES, Q_f value = 8,590) were selected. Their bioavailabilities relative to Fe sulfate (FeSO₄·7H₂O) for broilers fed with a conventional corn-soybean meal diet were evaluated during d 1 to 21 by investigating the effects of the above Fe sources and added Fe levels on the growth performance, hematological indices, Fe contents, activities and gene expressions of Fe-containing enzymes in various tissues of broilers.

Results: NaFeEDTA sources varied greatly in their chemical characteristics. Plasma Fe concentration (PI), transferrin saturation (TS), liver Fe content, succinate dehydrogenase (SDH) activities in liver, heart, and kidney, catalase (CAT) activity in liver, and SDH mRNA expressions in liver and kidney increased linearly (P < 0.05) with increasing levels of Fe supplementation. However, differences among Fe sources were detected (P < 0.05) only for PI, liver Fe content, CAT activity in liver, SDH activities in heart and kidney, and SDH mRNA expressions in liver and kidney. Based on slope ratios from multiple linear regressions of the above indices on daily dietary analyzed Fe intake, the average bioavailabilities of Fe-Prot ES, feed grade NaFeEDTA, and food grade NaFeEDTA relative to the inorganic FeSO₄·7H₂O (100%) for broilers were 139%, 155%, and 166%, respectively.

Conclusions: The bioavailabilities of organic Fe sources relative to FeSO₄·7H₂O were closely related to their Q_f values, and NaFeEDTA sources with higher Q_f values showed higher Fe bioavailabilities for broilers fed with a conventional corn-soybean meal diet.

Background: Dairy cows are at high risk of fatty liver disease in early lactation, but current preventative measures are not always effective. Cows with fatty liver have lower circulating branched-chain amino acid (BCAA) concentrations whereas cows with high circulating BCAA levels have low liver triglyceride (TG). Our objective was to determine the impact of BCAA and their corresponding ketoacids (branched-chain ketoacids, BCKA) on production performance and liver TG accumulation in Holstein cows in the first 3 weeks postpartum.

Methods: Thirty-six multiparous Holstein cows were used in a randomized block design experiment. Cows were abomasally infused for the first 21 d postpartum with solutions of 1) saline (CON, n = 12); 2) BCA (67 g valine, 50 g leucine, and 34 g isoleucine, n = 12); and 3) BCK (77 g 2-ketovaline calcium salt, 57 g 2-ketoleucine calcium salt, and 39 g 2-ketoisoleucine calcium salt, n = 12). All cows received the same diet. Treatment effects were determined using PROC GLIMMIX in SAS.

Results: No differences were detected for body weight, body condition score, or dry matter intake averaged over the first 21 d postpartum. Cows receiving BCK had significantly lower liver TG concentrations compared to CON (6.60% vs. 4.77%, standard error of the mean (SEM) 0.49) during the first 3 weeks of lactation. Infusion of BCA increased milk yield (39.5 vs. 35.3 kg/d, SEM 1.8), milk fat yield (2.10 vs. 1.69 kg/d, SEM 0.08), and lactose yield (2.11 vs. 1.67 kg/d, SEM 0.07) compared with CON. Compared to CON, cows receiving BCA had lower plasma glucose (55.0 vs. 59.2 mg/dL, SEM 0.86) but higher β-hydroxybutyrate (9.17 vs. 6.00 mg/dL, SEM 0.80).

Conclusions: Overall, BCAA supplementation in this study improved milk production, whereas BCKA supplementation reduced TG accumulation in the liver of fresh cows.

Background: Stocker cattle diet and management influence beef cattle performance during the finishing stage, but knowledge of the dynamics of the rumen microbiome associated with the host are lacking. A longitudinal study was conducted to determine how the feeding strategy from the stocker to the finishing stages of production affects the temporal dynamics of rumen microbiota. During the stocker phase, either dry hay or wheat pasture were provided, and three levels of monensin were administrated. All calves were then transported to a feedlot and received similar finishing diets with or without monensin. Rumen microbial samples were collected on d 0, 28, 85 during the stocker stage (S0, S28 and S85) and d 0, 14, 28, 56, 30 d before slaughter and the end of the trial during the finishing stage (F0, F14, F28, F56, Pre-Ba, and Final). The V4 region of the bacterial 16S rRNA gene of 263 rumen samples was sequenced.

Results: Higher alpha diversity, including the number of observed bacterial features and the Shannon index, was observed in the stocker phase compared to the finishing phase. The bacterial amplicon sequence variants (ASVs) differentiating different sampling time points were identified. Dietary treatments during the stocker stage temporally impact the dynamics of rumen microbiota. For example, shared bacteria, including Bacteroidales (ASV19) and Streptococcus infantarius (ASV94), were significantly higher in hay rumen on S28, S85, and F0, while Bacteroidaceae (ASV11) and Limivicinus (ASV15) were more abundant in wheat. Monensin affected rumen microbial composition at a specific time. Transportation to feedlot significantly influenced microbiome structure and diversity in hay-fed calves. Bacterial taxa associated with body weight were classified, and core microbiotas interacted with each other during the trial.

Conclusions: In summary, the temporal dynamics of the rumen microbiome in cattle at the stocker and finishing stage are influenced by multiple factors of the feeding strategy. Diet at the stocker phase may temporarily affect the microbial composition during this stage. Modulating the rumen microbiome in the steers at the stocker stage affects the microbial interactions and performance in the finishing stage.

Oxidative stress has been associated with a number of physiological problems in swine, including reduced production efficiency. Recently, although there has been increased research into regulatory mechanisms and antioxidant strategies in relation to oxidative stress-induced pig production, it remains so far largely unsuccessful to develop accurate models and nutritional strategies for specific oxidative stress factors. Here, we discuss the dose and dose intensity of the causes of oxidative stress involving physiological, environmental and dietary factors, recent research models and the antioxidant strategies to provide theoretical guidance for future oxidative stress research in swine.

Background: The benefits of combining benzoic acid and essential oils (BAO) to mitigate intestinal impairment during the weaning process have been well established, while the detailed underlying mechanism has not been fully elucidated. Previous research has primarily focused on the reparative effects of BAO on intestinal injury, while neglecting its potential in enhancing intestinal stress resistance.

Methods: In this study, we investigated the pre-protective effect of BAO against LPS-induced stress using a modified experimental procedure. Piglets were pre-supplemented with BAO for 14 d, followed by a challenge with LPS or saline to collect blood and intestinal samples.

Results: Our findings demonstrated that BAO supplementation led to significant improvements in piglets' final weight, average daily gain, and feed intake/body gain ratio. Additionally, BAO supplementation positively influenced the composition of intestinal microbiota, increasing beneficial Actinobacteriota and Alloprevotella while reducing harmful Desulfobacterota, Prevotella and Oscillospira. Furthermore, BAO supplementation effectively mitigated oxidative disturbances and inflammatory responses induced by acute LPS challenge. This was evidenced by elevated levels of T-AOC, SOD, and GSH, as well as decreased levels of MDA, TNF-α, and IL-6 in the plasma. Moreover, piglets subjected to LPS challenge and pre-supplemented with BAO exhibited significant improvements in intestinal morphological structure and enhanced integrity, as indicated by restored expression levels of Occludin and Claudin-1 compared to the non-supplemented counterparts. Further analysis revealed that BAO supplementation enhanced the jejunal antioxidative capacity by increasing GSH-Px levels and decreasing MDA levels under the LPS challenge and stimulated the activation of the Nrf2 signaling pathway. Additionally, the reduction of TLR4/NF-κB/MAPK signaling pathways activation and proinflammatory factor were also observed in the jejunal of those piglets fed with BAO.

Conclusions: In summary, our study demonstrates that pre-supplementation of BAO enhances the anti-stress capacity of weaned piglets by improving intestinal microbiota composition, reinforcing the intestinal barrier, and enhancing antioxidative and anti-inflammatory capabilities. These effects are closely associated with the activation of Nrf2 and TLR4/NF-κB/MAPK signaling pathways.

Background: Diarrhea is a major cause of reduced growth and mortality in piglets during the suckling and weaning periods and poses a major threat to the global pig industry. Diarrhea and gut dysbiosis may in part be prevented via improved early postnatal microbial colonization of the gut. To secure better postnatal gut colonization, we hypothesized that transplantation of colonic or gastric content from healthy donors to newborn recipients would prevent diarrhea in the recipients in the post-weaning period. Our objective was to examine the impact of transplanting colonic or gastric content on health and growth parameters and paraclinical parameters in recipient single-housed piglets exposed to a weaning transition and challenged with enterotoxigenic Escherichia coli (ETEC).

Methods: Seventy-two 1-day-old piglets were randomized to four groups: colonic microbiota transplantation (CMT, n = 18), colonic content filtrate transplantation (CcFT, n = 18), gastric microbiota transplantation (GMT, n = 18), or saline (CON, n = 18). Inoculations were given on d 2 and 3 of life, and all piglets were milk-fed until weaning (d 20) and shortly after challenged with ETEC (d 24). We assessed growth, diarrhea prevalence, ETEC concentration, organ weight, blood parameters, small intestinal morphology and histology, gut mucosal function, and microbiota composition and diversity.

Results: Episodes of diarrhea were seen in all groups during both the milk- and the solid-feeding phase, possibly due to stress associated with single housing. However, CcFT showed lower diarrhea prevalence on d 27, 28, and 29 compared to CON (all P < 0.05). CcFT also showed a lower ETEC prevalence on d 27 (P < 0.05). CMT showed a higher alpha diversity and a difference in beta diversity compared to CON (P < 0.05). Growth and other paraclinical endpoints were similar across groups.

Conclusion: In conclusion, only CcFT reduced ETEC-related post-weaning diarrhea. However, the protective effect was marginal, suggesting that higher doses, more effective modalities of administration, longer treatment periods, and better donor quality should be explored by future research to optimize the protective effects of transplantation.

Background: This study investigated the effects of inorganic and organic minerals on physiological responses, oxidative stress reduction, and rumen microbiota in Holstein bull calves (123.81 ± 9.76 kg; 5 months old) during short-term heat stress (HS) and recovery periods. Eight Holstein calves were randomly assigned to four treatment groups: no mineral supplementation (Con), inorganic minerals (IM), organic minerals (OM), and high-concentration organic minerals (HOM) and two thermal environments (HS and recovery) using 4 × 2 factorial arrangement in a crossover design of four periods of 35 d. Calves were maintained in a temperature-controlled barn. The experimental period consisted of 14 d of HS, 14 d of recovery condititon, and a 7-d washing period.

Results: Body temperature and respiration rate were higher in HS than in the recovery conditions (P < 0.05). Selenium concentration in serum was high in the HOM-supplemented calves in both HS (90.38 μg/dL) and recovery periods (102.00 μg/dL) (P < 0.05). During the HS period, the serum cortisol was 20.26 ng/mL in the HOM group, which was 5.60 ng/mL lower than in the control group (P < 0.05). The total antioxidant status was the highest in the OM group (2.71 mmol Trolox equivalent/L), followed by the HOM group during HS, whereas it was highest in the HOM group (2.58 mmol Trolox equivalent/L) during the recovery period (P < 0.05). Plasma malondialdehyde and HSP70 levels were decreased by HOM supplementation during the HS and recovery periods, whereas SOD and GPX levels were not significantly affected (P > 0.05). The principal coordinate analysis represented that the overall rumen microbiota was not influenced by mineral supplementation; however, temperature-induced microbial structure shifts were indicated (PERMANOVA: P < 0.05). At the phylum level, Firmicutes and Actinobacteria decreased, whereas Fibrobacteres, Spirochaetes, and Tenericutes increased (P < 0.05), under HS conditions. The genus Treponema increased under HS conditions, while Christensenella was higher in recovery conditions (P < 0.05).

Conclusion: HOM supplementation during HS reduced cortisol concentrations and increased total antioxidant status in Holstein bull calves, suggesting that high organic mineral supplementation may alleviate the adverse effects of HS.