Effect of Feeding Level on Growth and Slaughter Performance, and Allometric Growth of Tissues and Organs in Female Growing Saanen Dairy Goats.

This study aimed to investigate the effect of feeding level on the growth and slaughter performance, and allometric growth of tissues and organs in female growing dairy goats. The trial included 10-20 and 20-30 kg weight stages with 48 female goat kids. The 24 goat kids in each stage were divided into 8 blocks based on weight, with 3 kids per block. Then, three kids from each block were randomly assigned to one of the three treatments, namely ad libitum (AL100), 70% of ad libitum (AL70), or 40% of ad libitum (AL40). The slaughter trial was conducted when the AL100 kids reached the target weight of 20 or 30 kg. The results showed that the ADG and feed conversion rate showed a linear decline as the feed level decreased (p < 0.05). Compared with the AL70 and AL100 groups, the AL40 group exhibited lower shrunk body weight, empty body weight, hot carcass weight, net meat rate, carcass meat rate, and visceral fat weight (p < 0.05) in both stages. Moreover, the AL40 group showed lower weights for skin and mohair, blood, rumen, small intestine, large intestine, mammary gland, and uterus than the AL70 and AL100 groups (p < 0.05) in both stages. However, feeding level did not affect organ indices in the two stages (p > 0.05). The bone, skin and mohair were isometric (b ≈ 1), but the muscle, visceral fat, and most internal organs were positive (b > 1) in both stages. In conclusion, feeding level affects the growth and development of dairy goats, which vary depending on the body weight stage and specific tissues and organs.

Metagenomics reveals the temporal dynamics of the rumen resistome and microbiome in goat kids.

BACKGROUND: The gut microbiome of domestic animals carries antibiotic resistance genes (ARGs) which can be transmitted to the environment and humans, resulting in challenges of antibiotic resistance. Although it has been reported that the rumen microbiome of ruminants may be a reservoir of ARGs, the factors affecting the temporal dynamics of the rumen resistome are still unclear. Here, we collected rumen content samples of goats at 1, 7, 14, 28, 42, 56, 70, and 84 days of age, analyzed their microbiome and resistome profiles using metagenomics, and assessed the temporal dynamics of the rumen resistome in goats at the early stage of life under a conventional feeding system. RESULTS: In our results, the rumen resistome of goat kids contained ARGs to 41 classes, and the richness of ARGs decreased with age. Four antibiotic compound types of ARGs, including drugs, biocides, metals, and multi-compounds, were found during milk feeding, while only drug types of ARGs were observed after supplementation with starter feed. The specific ARGs for each age and their temporal dynamics were characterized, and the network inference model revealed that the interactions among ARGs were related to age. A strong correlation between the profiles of rumen resistome and microbiome was found using Procrustes analysis. Ruminal Escherichia coli within Proteobacteria phylum was the main carrier of ARGs in goats consuming colostrum, while Prevotella ruminicola and Fibrobacter succinogenes associated with cellulose degradation were the carriers of ARGs after starter supplementation. Milk consumption was likely a source of rumen ARGs, and the changes in the rumen resistome with age were correlated with the microbiome modulation by starter supplementation. CONCLUSIONS: Our data revealed that the temporal dynamics of the rumen resistome are associated with the microbiome, and the reservoir of ARGs in the rumen during early life is likely related to age and diet. It may be a feasible strategy to reduce the rumen and its downstream dissemination of ARGs in ruminants through early-life dietary intervention. Video Abstract.

Altered microbiota, antimicrobial resistance genes, and functional enzyme profiles in the rumen of yak calves fed with milk replacer.

IMPORTANCE: Yaks, as ruminants inhabiting high-altitude environments, possess a distinct rumen microbiome and are resistant to extreme living conditions. This study investigated the microbiota, resistome, and functional gene profiles in the rumen of yaks fed milk or milk replacer (MR), providing insights into the regulation of the rumen microbiome and the intervention of antimicrobial resistance in yaks through dietary methods. The abundance of Prevotella members increased significantly in response to MR. Tetracycline resistance was the most predominant. The rumen of yaks contained multiple antimicrobial resistance genes (ARGs) originating from different bacteria, which could be driven by MR, and these ARGs displayed intricate and complex interactions. MR also induced changes in functional genes. The enzymes associated with fiber degradation and butyrate metabolism were activated and showed close correlations with Prevotella members and butyrate concentration. This study allows us to deeply understand the ruminal microbiome and ARGs of yaks and their relationship with rumen bacteria in response to different milk sources.

Effects of maternal calcium propionate supplementation on offspring productivity and meat metabolomic profile in sheep.

This study determined the effect of dietary calcium propionate (CaPr) as a source of energy supplementation during the First Half of Gestation (FMG), the Second Half of Gestation (SMG), and during All Gestation (AG), on offspring post-weaning growth performance, meat quality, and meat metabolomic profile. Thirty-one pregnant ewes were assigned to one of four treatments: a) supplementation of 30 gd-1 of CaPr during the first half of gestation (day 1 to day 75, n = 8) (FMG); b) supplementation of 30 gd-1 of CaPr during the second half of gestation (day 76 to day 150, n = 8) (SMG); c) supplementation of 30 gd-1 of CaPr during all gestation (AG, n = 8); d) no CaPr supplementation (control; CS, n = 7). The ewes were ad libitum fed a basal diet based on oat hay and corn silage. Ewes were distributed in a completely randomized unbalanced design to four treatments. The FMG group had lower (P ≤ 0.05) birth weight and weaning weight than the CS group. However, the average daily gain was similar across all treatments. Empty body weight and FMG had lower values (P ≤ 0.05) than the other groups. Both FMG and AG had lower hot carcass weight (P ≤ 0.05) compared to CS, while CaPr treatments resulted in reduced hot carcass yield (P ≤ 0.05). Meat color and texture were similar among treatments. A principal component analysis between gestation stages showed a trend for separating CS and FMG from SMG and AG, and that was explained by 93.7% of the data variability (PC1 = 87.9% and PC2 = 5.8%). Regarding meat metabolomic profile, 23 compounds were positively correlated between all treatments. Only 2 were negatively correlated (eicosane and naphthalene 1,2,3); but tetradecanoic acid, hexadecane, undecane 5-methyl, (-)-alpha, hexadecenoic acid, octadecanoic acid, and octadecane had a highly significant correlation (P ≤ 0.05). Overall, dam supplementation with CaPr during different periods of gestation provoked changes in meat metabolites related to the biosynthesis of fatty acids in lambs without negative changes in lamb's growth performance and carcass quality.

Transcriptomic and metabolomic insights into the roles of exogenous ß-hydroxybutyrate acid for the development of rumen epithelium in young goats.

Beta-hydroxybutyric acid (BHBA), as one of the main metabolic ketones in the rumen epithelium, plays critical roles in cellular growth and metabolism. The ketogenic capacity is associated with the maturation of rumen in young ruminants, and the exogenous BHBA in diet may promote the rumen development. However, the effects of exogenous BHBA on rumen remain unknown. This is the first study to investigate the mechanisms of BHBA on gene expression and metabolism of rumen epithelium using young goats as a model through multi-omics techniques. Thirty-two young goats were divided into control, low dose, middle dose, and high dose groups by supplementation of BHBA in starter (0, 3, 6, and 9 g/day, respectively). Results demonstrated the dietary of BHBA promoted the growth performance of young goats and increased width and length of the rumen papilla (P < 0.05). Hub genes in host transcriptome that were positively related to rumen characteristics and BHBA concentration were identified. Several upregulated hub genes including NDUFC1, NDUFB4, NDUFB10, NDUFA11 and NDUFA1 were enriched in the gene ontology (GO) pathway of nicotinamide adenine dinucleotide (NADH) dehydrogenase (ubiquinone) activity, while ATP5ME, ATP5PO and ATP5PF were associated with ATP synthesis. RT-PCR revealed the expression of genes (HMGCS2, BDH1, SLC16A3, etc.) associated with lipolysis increased significantly by BHBA supplementation (P < 0.05). Metabolomics indicated that some metabolites such as glucose, palmitic acid, cortisol and capric acid were also increased (P < 0.05). This study revealed that BHBA promoted rumen development through altering NADH balance and accelerating lipid metabolism, which provides a theoretical guidance for the strategies of gastrointestinal health and development of young ruminants.

Physical, Metabolic, and Microbial Rumen Development in Goat Kids: A Review on the Challenges and Strategies of Early Weaning.

The digestive system of newborn ruminant functions is similar to monogastric animals, and therefore milk flows into the abomasum instead of rumen for digestion. The rumen undergoes tremendous changes over time in terms of structure, function, and microbiome. These changes contribute to the smooth transition from the dependence on liquid diets to solid diets. Goat kids are usually separated at early ages from their dams in commercial intensive systems. The separation from dams minimizes the transfer of microbiota from dams to newborns. In this review, understanding how weaning times and methodologies could affect the normal development and growth of newborn goats may facilitate the development of new feeding strategies to control stress in further studies.

Early Solid Diet Supplementation Influences the Proteomics of Rumen Epithelium in Goat Kids.

It is well known that solid diet supplementation in early life can significantly promote rumen development and metabolic function in young ruminants. However, the changes in the expressed proteome and related metabolism in rumen epithelium in response to a supplemented solid diet remain unclear. In this study, rumen epithelial tissue from goats in three diet regimes including milk replacer only (MRO), milk replacer supplemented concentrate (MRC), and milk replacer supplemented concentrate plus alfalfa pellets (MCA) were collected for measurement of the expression of epithelial proteins using proteomic technology (six per group). The results showed that solid diet significantly improved the growth performance of goats, enhanced the ability of rumen fermentation, and promoted the development of epithelial papilla (p < 0.05). Proteome analysis revealed the distinct difference in the expressed protein in the MRC and MCA group compared with the MRO group (42 upregulated proteins and 79 downregulated proteins in MRC; 38 upregulated proteins and 73 downregulated proteins in MCA). Functional analysis showed that solid diet supplementation activated a variety of molecular functions in the epithelium, including protein binding, ATP binding, structural constituent of muscle, etc., in the MRC and MCA groups. Meanwhile, the expression of proteins related to fatty acid metabolism, the PPAR signaling pathway, valine, leucine, and isoleucine degradation, and butanoate metabolism were upregulated, being stimulated by solid feed. In contrast, the proteins associated with carbohydrate digestion and absorption and glycosaminoglycan degradation were downregulated. In addition, the protein expression of enzymes involved in ketone body synthesis in the rumen was generally activated, which was caused by solid feed. In summary, solid feed promoted the development of rumen epithelium by changing the expression of proteins related to fatty acid metabolism, energy synthesis, and signal transduction. The ketone body synthesis pathway might be the most important activated pathway, and provides energy for rumen development.

Advances in the Application of Phytogenic Extracts as Antioxidants and Their Potential Mechanisms in Ruminants.

Under current breeding conditions, multiple stressors are important challenges facing animal husbandry in achieving animal wellbeing. For many years, the use of antibiotics has been a social concern in the livestock industry. With the implementation of the non-antibiotics policy, there is an urgent need to find relevant technologies and products to replace antibiotics and to solve the problem of disease prevention during animal growth. Phytogenic extracts have the unique advantages of being natural and extensive sources, having a low residue, and being pollution-free and renewable. They can relieve the various stresses, including oxidative stress, on animals and even control their inflammation by regulating the signaling pathways of proinflammatory cytokines, improving animal immunity, and improving the structure of microorganisms in the gastrointestinal tract, thereby becoming the priority choice for improving animal health. In this study, we reviewed the types of antioxidants commonly used in the livestock industry and their applicable effects on ruminants, as well as the recent research progress on their potential mechanisms of action. This review may provide a reference for further research and for the application of other phytogenic extracts and the elucidation of their precise mechanisms of action.

Rumen microbiota-host transcriptome interaction mediates the protective effects of trans-10, cis-12 CLA on facilitating weaning transition of lambs.

Developing alternatives to antibiotics for prevention of gastrointestinal dysbiosis in early-weaning farmed animals is urgently needed. This study was to explore the potential effects of trans-10, cis-12 conjugated linoleic acid (CLA) on maintaining ruminal homeostasis of young ruminants during the weaning transition period. Thirty neonatal lambs were selected (6 lambs per group) and euthanized for rumen microbial and epithelial analysis. The lambs were weaned at 28 d and experienced the following 5 treatments: euthanized on d 28 as the pre-weaning control (CON0), fed starter feed for 5 (CON5) or 21 (CON21) d, fed starter feed with 1% of CLA supplemented for 5 (CLA5) or 21 (CLA21) d. Results showed that the average daily weight gain and dry matter intake were significantly higher in CLA5 than CON5 group. As compared with the CON5 and CON21 group, the relative abundances of volatile fatty acid (VFA) producing bacteria including Bacteroides, Treponema, Parabacteroides and Anaerovibrio, as well as the concentrations of acetate, butyrate and total VFA were significantly increased in CLA5 and CLA21 group, respectively. Integrating microbial profiling and epithelial transcriptome results showed that 7 downregulated inflammatory signaling-related host genes IL2RA, CXCL9, CD4, CCR4, LTB, SPP1, and BCL2A1 with CLA supplementation were significantly negatively correlated with both VFA concentration and VFA producing bacteria, while 3 (GPX2, SLC27A2 and ALDH3A1) and 2 (GSTM3 and GSTA1) upregulated metabolism-related genes, significantly positively correlated with either VFA concentration or VFA producing bacteria, respectively. To confirm the effects of CLA on epithelial signal transduction, in vitro experiment was further conducted by treating rumen epithelial cells without or with IL-17A + TNF-α for 12 h after pretreatment of 100 µM CLA or not (6 replicates per treatment). The results demonstrated the anti-inflammatory effect of CLA via suppressing the protein expression of NF-кB p-p65/p65 with the activation of peroxisome proliferator-activated receptor gamma (PPARγ). In conclusion, CLA supplementation enhanced the ruminal microbiota-driven transcriptional regulation in healthy rumen epithelial development via rumen VFA production, and CLA may therefore serve as an alternative way to alleviate early-weaning stress and improve physiological and metabolic conditions of young ruminants.

Dietary medium-chain fatty acid and Bacillus in combination alleviate weaning stress of piglets by regulating intestinal microbiota and barrier function.

The present study evaluated the effects of dietary medium-chain fatty acid (MCFA) and Bacillus on growth performance, nutrient digestibility, antioxidant capacity, colonic fermentation, and microbiota of weaning piglets. A total of 400 weaned piglets were randomly divided into 4 treatments, with 10 replicates per treatment and 10 pigs per replicate. The treatment included: basal diet (control, CON), basal diet with 0.588 g/kg MCFA (MCF), basal diet with 1.3 × 109 CFU/kg Bacillus (BAC), and basal diet with 0.588 g/kg MCFA and 1.3 × 109 CFU/kg Bacillus (SYN). Compared with CON group, the average daily gain of MCF and SYN in the early (1 to 9 d) and whole stage (1 to 36 d) of trail were improved (P < 0.05), the feed to gain ratio of MCF in later (10 to 36 d) and whole stage of trial were decreased (P < 0.05), and the diarrhea rate of SYN in the early stage (1 to 9 d) of trial decreased (P < 0.05). The digestibility of dry matter, ether extract, acid detergent fiber digestibility of MCF were decreased (P < 0.05) compared with CON. The serum d-lactic acid in MCF, BAC, and SYN were lower (P < 0.05) compared with CON group. Compared with CON group, the contents of total antioxidant capacity, superoxide dismutase, and glutathione peroxidase were greater (P < 0.05), whereas the content of malondialdehyde and the contents of colonic isobutyrate and isovalerate were lower (P < 0.05) in MCF. The microbial Shannon and Simpson diversity was lower in MCF (P < 0.05) than that in BAC and SYN. The relative abundance of Prevotella was greater (P < 0.05), whereas the Treponema and Oscillibacter were lower (P < 0.05) in MCF than that in BAC and SYN. In addition, the metabolic pathways of bacteria such as pentose phosphate pathway, adenosine nucleotides degradation II were enhanced (P < 0.05), whereas the pathways such as incomplete reductive TCA cycle, and TCA cycle IV (2-oxoglutarate decarboxylase) were decreased (P < 0.05) in MCF compared with BAC. The results indicated that dietary MCFA and Bacillus in combination improved the intestinal barrier function of piglets by changing the intestinal microbiota and its metabolic function, and finally alleviated the diarrhea rate in early weaning stage and improved growth performance in whole trial period. In addition, MCFA was effective in improving feed efficiency and antioxidant capacity of piglets.

Weaning is the most stressful stage in the growth of piglets. Weaning stress can reduce the feed intake of piglets, cause diarrhea and even death of piglets, and finally result in economic losses to livestock production. To alleviate the weaning stress of piglets after the prohibition of antibiotics in feed, this study evaluated the effect and mechanism of medium-chain fatty acid (MCFA) and Bacillus in combination on regulating the intestinal microbiota balance and health status of weaned piglets. It was found that dietary MCFA and Bacillus in combination improved the intestinal barrier function of piglets by changing the intestinal microbial community and metabolic pathway encoded by bacteria, and finally alleviated the diarrhea rate in the early weaning stage and improved the growth performance in whole trial period. In addition, MCFA was effective in improving feed efficiency and antioxidant capacity of piglets.

In Vitro Modulation of Rumen Fermentation by Microbiota from the Recombination of Rumen Fluid and Solid Phases.

Rumen microbiota transplantation (RMT) can improve rumen fermentation and ruminant performance. However, due to the microbial distinction in the fluid and solid phases, the current understanding of their specific roles in RMT is insufficient. Thus, this study was conducted to determine the effects of the microbiota from the recombination of the rumen fluid and solid phases on in vitro fermentation. The rumen fresh fluid (FF) and fresh solid (FS) phases were collected, and FS was washed for the fresh solid washing solution (FW). The fractions of FF, FS, and FW were autoclaved to obtain autoclaved fluid (AF), solid (AS), and washing solution (AW). Then, these phases were recombined to form eight treatments: FFFS, FFAS, FFFW, FFAW, AFFS, AFAS, AFFW, and AFAW. After 24 h of fermentation, the gas production in AFFS, FFFS, and FFAS was significantly higher than that of other groups. AFAS and AFAW had significantly lower alpha diversity than did other groups. The solid phase was enriched with fiber-degrading bacteria, including Treponema, Succinivibrio, and Ruminococcus. The fluid phase was dominated by Prevotella, Christensenellaceae R-7 group, and Rikenellaceae RC9 gut group. The washing solution had more Ruminobacter, Lachnospiraceae, and Fibrobacter. Moreover, the double-autoclaved phases displayed increased abundances of harmful bacteria, as AFAS and AFAW had higher Streptococcus and Prevotellaceae YAB2003 group abundances. A network analysis showed that the signature microbiota in AFAS and AFAW were negatively associated with the keystone microbiota in the other groups. In summary, the recombination of the solid phase and the autoclaved fluid phase had the best in vitro fermentation result, which provided certain references for RMT. IMPORTANCE This is the first study to systematically evaluate the in vitro fermentation efficiency of diets by bacteria harvested and recombined from the fluid and solid phases of rumen contents, and it took into account the effect of washing the rumen solid phase. Using "reconstituted rumen content", this study confirmed that bacteria from different fractions of the rumen digesta resulted in different fermentation production of diets and found the characteristic bacteria in each phase of rumen contents. Our data reveal that the bacteria in the solid phase have more positive effects on the in vitro fermentation parameters, that the combination of the autoclaved fluid phase and the fresh solid phase have the most ideal fermentation effect, and that the autoclave process significantly influenced the microbial composition and increased the abundance of harmful bacteria. This study provides a landmark reference for the future use of rumen microbiota transplantation to improve animal feed utilization and growth performance.

Dietary ß-hydroxybutyric acid improves the growth performance of young ruminants based on rumen microbiota and volatile fatty acid biosynthesis.

Introduction: The ketone body ß-hydroxybutyric acid (BHB) plays critical roles in cellular proliferation and metabolic fuel utilization; however, its effects on the rumen microbiota remain unknown. Methods: Here, three doses of BHB (low, medium, and high) were supplemented to early-weaned goat kids. Results: Compared with controls, the beneficial effects of BHB on growth and rumen development were observed in goats at 90 days of age (d). The low dose of dietary BHB increased the concentration of rumen acetate, propionate, and butyrate on d90. The sequencing results of the rumen microbiota revealed marked shifts in rumen microbial community structure after early-weaned goat kids consumed BHB for 2 months. The signature bacterial ASVs for each treatment were identified and were the main drivers contributing to microbial interactions in the rumen. The bacteria associated with rumen weight were also correlated with body weight. Some classified bacterial signatures, including Prevotella, Olsenella umbonate, and Roseburia faecis, were related to rumen volatile fatty acids and host development. Conclusion: Overall, dietary BHB altered rumen microbiota and environments in young goats, which contributed to rumen development and growth.

Effect of different dietary inclusion levels of whole plant green tomato (Physalis philadelphica) silage on nutrient intake and digestibility, and in vitro rumen fermentation kinetics in sheep.

Mexico has many agricultural by-products that can be used for animal feed, and green tomatoes are produced throughout the country and can be an alternative to overcome the high prices of cereal-based feeds. This study determined in vitro fermentation kinetics, production performance, nutrient intake, digestibility, and nitrogen balance from sheep supplemented with whole plant green tomato (GT) on corn silage (CS) based diets. For 21 days, eighteen Suffolk lambs (38 ± 4 kg of live weight) were grouped into three dietary GT inclusion levels to replace CS: a control diet based on 100% CS (GT0, 570 g /kg dry matter, DM), while 100 g/kg DM (GT100) and 200 g/kg DM (GT200) of GT were included as a replacement for CS. A completely randomized design was used to measure in vitro gas production, in vitro rumen fermentation, chemical composition, and in vivo parameters. In vitro gas production, "A" (ml/g DM), fermentation rates "B," (h-1), and "C" (h-½), were lower for GT200, while DM disappearance (mg/100mg) was lower for GT100 compared with GT0. Compared to GT0, GT100 and GT200 did not affect (P > 0.05) DM and organic matter (OM) intake (g/kgLW0.75). Ether extract intake was higher for GT0 and GT100 (P < 0.001) compared to GT200. Neutral detergent fiber (NDF) intake was higher (P < 0.05) for GT200 compared with GT0. Intake of lignin was higher (P < 0.001) for GT200 than that of GT0 and GT100. Digestibility coefficients for DM, OM, NDF, and Acid detergent fiber (ADF) were lower (P < 0.05) in GT100 than in the rest of the treatments. Nitrogen intake and N excreted in feces and urine were lower (P < 0.001) for GT0. N balance was negative for all treatments, being higher for GT200 (P < 0.05). Overall, the addition of GT at 100 or 200 g/kg DM in sheep diets negatively affects nutrient digestibility and N balance, so their dietary inclusion is not recommended.

Impact of dietary supplementation of ß-hydroxybutyric acid on performance, nutrient digestibility, organ development and serum stress indicators in early-weaned goat kids.

The objective of this study was to determine the effect of dietary supplementation of ß-hydroxybutyric acid (BHBA) on performance, nutrient digestibility, organ development, and serum composition in early-weaned goat kids. Sixty-four goat kids at 30 d of age were assigned to 4 treatments in a completely randomized design: 1) control (basal diet); 2) low (basal diet with 3 g/d per animal BHBA); 3) medium (basal diet with 6 g/d per animal BHBA; and 4) high (basal diet with 9 g/d per animal BHBA). Subsequently, 48 (6 kids per treatment) goat kids were randomly selected and slaughtered at 60 and 90 d of age. Compared with the control group, BHBA at low and high doses increased body weight (P < 0.05), average daily gain (P < 0.01), and average daily starter intake (P < 0.01). The BHBA improved organ development, especially at the lowest dose (P < 0.01). The digestibility of dry matter and crude protein increased with age (P < 0.05). However, BHBA did not affect nutrient digestibility. Compared with the control group, serum ceruloplasmin increased (P < 0.05) with high BHBA level at 90 d of age. However, the serum creatinine (P < 0.05) increased over time but was not affected by BHBA. The serum total antioxidant capacity and superoxide dismutase decreased with the high dose of BHBA at 90 d of age (P < 0.01). In contrast, the serum glutathione peroxidase and malondialdehyde increased with the high doses of BHBA (P < 0.01). Overall, low doses of BHBA were positive for growth performance, organ development, and health status against weaning stress. Whereas high doses of BHBA in the long term could negatively affect antioxidant status.

The Temporal Dynamics of Rumen Microbiota in Early Weaned Lambs.

Weaning affects the development of ruminal bacteria in lambs during early life. However, the temporal dynamics of rumen microbiota in early weaned lambs is unknown compared to conventionally weaned lambs. In this study, one group was reared with their dams (control, CON) and conventionally weaned at 49 days (d), while the other lambs were weaned at 21 d (early weaning, EW) using starter. Rumen microbial samples collected at 26, 35, and 63 d were used for next-generation sequencing. Here, we found that the abundance and diversity of rumen microbiota in EW were significantly lower at 26 and 35 d than the CON. Linear discriminant analysis Effect Size (LEfSe) analysis was performed to identify the signature microbiota for EW at these three ages. At 26 d, Prevotella 7, Syntrophococcus, Sharpea, Dialister, Pseudoscardovia, and Megasphaera in the rumen of the EW group had greater relative abundances. At 35 d, the Lachnospiraceae_NK3A20_group was enriched in CON. On 63 d, Erysipelotrichaceae_UCG-002 was abundant in EW. Syntrophococcus and Megaspheaera in EW lambs were abundant at 26 and 35 d, but kept similar to CON at 63 d. The relative abundance of Erysipelotrichaceae_UCG-002 at all-time points was consistently higher in the EW group. In conclusion, early weaning led to a significant decrease in rumen microbiota richness and diversity in the short term. The changes in rumen microbiota are associated with the persistence of weaning stress. The temporal dynamics of relative abundances of Syntrophococcus, Megasphaera, and Ruminococcaceae_UCG-014 reflect the weaning stress over a short period and rumen recovery after early weaning.

Solid diet manipulates rumen epithelial microbiota and its interactions with host transcriptomic in young ruminants.

Solid diet supplementation in the early life stages of ruminants could improve rumen microbiota and tissue development. However, most studies focus on bacteria in the rumen content community. The microbiota attached on rumen epithelium are rarely investigated, and their correlations with rumen content bacteria and host transcripts are unknown. In this study, rumen digesta attached in the epithelium from goats in three diet regimes (milk replacer only, milk replacer supplemented concentrate and milk replacer supplemented concentrate plus alfalfa pellets) were collected for measurement of the epithelial microbiota using next generation sequencing. Correspondingly, the rumen tissues of the same animals were measured with the host transcriptome. The distinct microbial structures and compositions between rumen content and epithelial communities were associated with solid diet supplementation. Regarding rumen development in pre-weaning ruminants, a solid diet, especially its accompanying neutral detergent fibre nutrients, was the most significant driver that influenced the rumen microbiota and epithelium gene expression. Compared with content bacteria, rumen epithelial microbiota had a stronger association with the host transcriptome. The host transcriptome correlated with host phenotypes were associated with rumen epithelial microbiota and solid diet. This study reveals that the epithelial microbiota is crucial for proper rumen development, and solid diet could improve rumen development through both the rumen content and epithelial microbiota.

Predicting the Digestive Tract Development and Growth Performance of Goat Kids Using Sigmoidal Models.

The transition from monogastric to rumination stage is crucial in ruminants' growth to avoid stressors-weaning and neonatal mortalities. Poor growth of the digestive tract could adversely affect the performance of the animal. Modeling informative growth curves is of great importance for a better understanding of the effective development pattern, in order to optimize feeding management system, and to achieve more production efficiency. However, little is known about the digestive tract growth curves. For this reason, one big goat farm of Laiwu black breed was chosen as a basis of this study. Forty-eight kids belonging to eight-time points (1, 7, 14, 28, 42, 56, 70, and 84 d; 6 kids for each) were selected and slaughtered. The body weight, body size indices, rumen pH, and stomach parts were determined and fitted to the polynomial and sigmoidal models. In terms of goodness of fit criteria, the Gompertz model was the best model for body weight, body oblique length, tube, and rumen weight. Moreover, the Logistic model was the best model for carcass weight, body height, and chest circumference. In addition, the Quadratic model showed the best fit for dressing percentage, omasum weight, abomasum weight, and rumen volume. Moreover, the cubic model best fitted the ruminal pH and reticulum percentage. The Weibull model was the best model for the reticulum weight and omasum percentage, while the MMF model was the best model describing the growth of chest depth, rumen percentage, and abomasum percentage. The model parameters, R squared, inflection points, area under curve varied among the different dependent variables. The Pearson correlation showed that the digestive tract development was more correlated with age than body weight, but the other variables were more correlated with body weight than age. The study demonstrated the use of empirical sigmoidal and polynomial models to predict growth rates of the digestive tract at relevant age efficiently.

Multiomics analysis reveals the presence of a microbiome in the gut of fetal lambs.

OBJECTIVE: Microbial exposure is critical to neonatal and infant development, growth and immunity. However, whether a microbiome is present in the fetal gut prior to birth remains debated. In this study, lambs delivered by aseptic hysterectomy at full term were used as an animal model to investigate the presence of a microbiome in the prenatal gut using a multiomics approach. DESIGN: Lambs were euthanised immediately after aseptic caesarean section and their cecal content and umbilical cord blood samples were aseptically acquired. Cecal content samples were assessed using metagenomic and metatranscriptomic sequencing to characterise any existing microbiome. Both sample types were analysed using metabolomics in order to detect microbial metabolites. RESULTS: We detected a low-diversity and low-biomass microbiome in the prenatal fetal gut, which was mainly composed of bacteria belonging to the phyla Proteobacteria, Actinobacteria and Firmicutes. Escherichia coli was the most abundant species in the prenatal fetal gut. We also detected multiple microbial metabolites including short chain fatty acids, deoxynojirimycin, mitomycin and tobramycin, further indicating the presence of metabolically active microbiota. Additionally, bacteriophage phiX174 and Orf virus, as well as antibiotic resistance genes, were detected in the fetal gut, suggesting that bacteriophage, viruses and bacteria carrying antibiotic resistance genes can be transmitted from the mother to the fetus during the gestation period. CONCLUSIONS: This study provides strong evidence that the prenatal gut harbours a microbiome and that microbial colonisation of the fetal gut commences in utero.

Effects of Age and Dietary Factors on the Blood Beta-Hydroxybutyric Acid, Metabolites, Immunoglobulins, and Hormones of Goats.

The study was aimed to examine the effects of age and dietary beta-hydroxybutyric acid (BHBA) on blood BHBA and blood health indicators in goat kids. Thirty male goats of five ages (1, 2, 3, 6, and 12 months old) were selected for blood sampling to determine the influence of age. Another 64 goat kids (half males and half females) were weaned at 1 month old and fed with starter diets with control, low, medium, and high BHBA doses (0, 3, 6, and 9 g/animal/day, respectively). Six goats per treatment were selected for blood analysis at 2 and 3 months of age. There were significant effects (p < 0.01) of ages on the blood parameters of goat kids. The 6- and 12-month-old goats showed significantly lower blood total protein, globulin, BHBA, IgA, and IgM concentrations than did young goats, while they had a higher albumin-to-globulin ratio than young goats. The blood glucose decreased (p < 0.01) and IgG increased over time (p < 0.01). In blood, growth hormone (GH) and insulin-like growth factor I (IGF-I) were lower (p < 0.01) at 1- and 3-month-old goats than 12-month-old goats. The high dietary BHBA improved (p < 0.05) the ratio of albumin to globulin of 2-month-old kids compared with control. The blood GH and IGF-I were lower (p < 0.01) in the medium BHBA dose at 2 months of age than control. These results suggested that age greatly impacted blood composition, especially around weaning, and dietary BHBA showed beneficial regulating effects on blood total protein level in young goats.

Longitudinal Investigation of the Gut Microbiota in Goat Kids from Birth to Postweaning.

Early microbial colonization in the gut impacts animal performance and lifelong health. However, research on gut microbial colonization and development in young ruminants, especially after weaning, is currently limited. In this study, next-generation sequencing technology was performed to investigate the temporal dynamic changes of the microbial community in the jejunum and colon of goats at 1, 7, 14, 28, 42, 56, 70, and 84 days (d) of age. As age increased, significant increases in microbial diversity, including the number of Observed OTUs and the Shannon Index, were observed in both the jejunum and colon. Regarding beta diversity, significant shifts in community membership and structure from d1 to d84 were observed based on both Bray-Curtis and Jaccard distances. With increasing age, dominant genera in the jejunum shifted from Lactobacillus to unclassified Ruminococcaceae, unclassified Lachnospiraceae and unclassified Clostridiales through starter supplementation, whereas colonic dominant genera changed from Lactobacillus and Butyricicoccus, within d1-d28, to unclassified Ruminococcaceae, unclassified Clostridiales and Campylobacter after solid diet supplementation. The linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed bacterial features that are stage-specific in the jejunum and colon, respectively. In the jejunum and colon, a significantly distinct structure and membership of the microbiota was observed across all ages. The growth stage-associated microbiota in each gut compartment was also identified as a marker for biogeography. Our data indicate the temporal and spatial differences of the gut microbiota in goats are important for their performance and health. Early microbial colonization can influence microbial composition in later life (e.g., post-weaning phase). This study provides insights that the temporal dynamics of gut microbiota development from newborn to post-weaning can aid in developing feeding strategies to improve goat health and production.