Feeding colostrum and transition milk facilitates digestive tract functionality recovery from feed restriction and fasting of dairy calves

The objective of this study was to evaluate the digestive tract recovery and metabolism of feeding either bovine colostrum (BC), transition milk (TM), or milk replacer (MR) after an episode of feed restriction and fasting (FRF) in dairy calves. Thirty-five Holstein male calves (22 ± 4.8 d old) were involved in a 50-d study. After 3 d of feeding 2 L of rehydration solution twice daily and 19 h of fasting (d 1 of study), calves were randomly assigned to one of the 5 feeding treatments (n = 7): calves were offered either pooled BC during 4 (C4) or 10 (C10) days, pooled TM during 4 (TM4) or 10 (TM10) days, or MR for 10 d (CTRL) at the rate of 720 g/d DM content. Then, all calves were fed the same feeding program, gradually decreasing MR from 3 L twice daily to 2 L once daily at 12.5% DM until weaning (d 42), and concentrate feed, water, and straw were offered ad libitum until d 50. Citrulline, Cr-EDTA, β-hydroxybutyrate (BHB), and nonesterified fatty acids (NEFA) in serum and complete blood count (CBC) were determined on d -3, 1, 2, 5, and 11 relative to FRF, except BHB and NEFA at d -3. Volatile fatty acids (VFA), lactoferrin (LTF), IgA, and microbiota (Firmicutes to Bacteroidetes ratio and Fecalis prausnitzii) were analyzed in feces on d 5 and 11 before the morning feeding. Health scores were recorded daily from d -3 to d 14 as well as d 23 and 30. Feed concentrate, MR, and straw intake were recorded daily, and body weight on d -3, 1, 2, 5, and 11 and weekly afterward. Calf performance, intake, serum Cr-EDTA, CBC, fecal LTF concentrations and microbiota parameters were similar among treatments throughout the study. Serum NEFA concentrations were greater in TM4, TM10 and C10 calves compared with the CTRL ones from d 2 to 11, and after the FRF, serum concentrations of BHB were lower in CTRL calves than in the other treatments, and on d 11, serum BHB concentrations in the long treatments (C10 and TM10) remained greater than those in the shorter ones (C4 and TM4) and CTRL. Serum citrulline concentrations were similar on d -3 and 1 in all treatments, but they were greater in C4, C10, TM4, and TM10 on d 2 and 5, and on d 11 they were only greater in C10 and TM10 than in CTRL calves. Fecal IgA concentrations tended to be greater in C10 than in CTRL, TM4, and TM10 calves, and in C4 and TM10 than in CTRL animals. Fecal propionate proportion was lesser in C10 than in CTRL, TM4, and TM10 calves, while butyrate was greater in C4 and C10 than in TM4 and CTRL calves. The proportion of non-normal fecal scores of C10 fed calves was greater than TM4 and TM10 calves. Results showed that TM and BC may help to recover intestinal functionality, provide gut immune protection, and increase liver fatty acid oxidation in calves after a FRF episode.

Benefits of barley straw as a forage for dairy calves before and after weaning

The aim of this study was to assess the potential consequences on calf intake, performance, behavior, ruminal microbiome, and ruminal epithelium development of combining the inclusion of chopped barley straw and alfalfa hay during the pre- and postweaning periods keeping concentrate to forage ratio constant among dietary treatments. Forty-five Holstein calves (44 ± 5.7 kg of body weight [BW] and 3 ± 1.5 d of age) individually penned were blocked by BW and randomly assigned to a common pellet concentrate fed ad libitum along with one of following forage feeding strategies: barley straw before and after weaning (S-S), barley straw before and alfalfa hay after weaning (S-A), or alfalfa hay before and after weaning (A-A). All calves received the same milk replacer regimen. Forage was supplied in a separated bucket at the rate of 7.5% (preweaning) and 15% (postweaning) of total solid feed intake of the previous day. Feed intake and BW were recorded daily and weekly, respectively. Rumen samples were obtained via a stomach tube at 53, 66, and 87 d and were composite in 3 samples of 5 animals each for subsequent rumen microbiome analysis. A rumen epithelium sample was taken by endoscopy at 90 d to assess gene expression of OCLN, CLDN4, SLC9A1, SLC9A3, SLC16A1, SLC16A4, IL6, and TGFB1. Data were analyzed with a mixed-effects model accounting for the fixed effects of block, forage, week of study, and their interaction, and calf as a random effect. The type of forage fed did not affect concentrate feed, forage, or total DM intake before weaning. However, S-A and A-A calves consumed less concentrate feed and S-A calves grew at a lower rate after weaning than S-S calves. Expression of the gene coding for SLC16A1 in the rumen epithelium was greatest in S-S among treatments. Rumen microbiome did not differ among treatments, while the relative abundance of Acidaminococcus and Selenomas genera increased, while Alloprevotella, Bifidobaterium, Olsenella, and Succiclasticum genera decreased with age. In conclusion, feeding barley straw before and after weaning was more effective than feeding alfalfa hay in promoting concentrate feed intake after weaning and fostering an increase in the expression of SLC16A1 in the rumen epithelium.

Changes in the rumen and colon microbiota and effects of live yeast dietary supplementation during the transition from the dry period to lactation of dairy cows

The first objective of this study was to evaluate the dynamics and their potential association with animal performance of the microbiota in both the rumen and colon of dairy cows as they move from a nonlactation to a lactation ration. The second objective was to assess the potential effects on the microbiota of live yeast supplementation. Twenty-one Holstein cows were split in 2 treatments consisting of 1 × 10¹⁰ cfu/d of live yeast (LY; n = 10) or no supplementation (control; n = 11) starting 21 d before until 21 d after calving. At 14 d before and 7 and 21 d after calving, samples of rumen and colon digesta were obtained from each cow using an endoscope. Total DNA was extracted and submitted to high-throughput sequencing. Shannon diversity index, in both the rumen and colon, was unaffected by LY; however, in the rumen it was lowest 7 d after calving and returned to precalving values at 21 d in milk, whereas in the colon it was greatest 14 d before calving but decreased after calving. In the rumen, LY supplementation increased the relative abundance (RA) of Bacteroidales (group UCG-001), Lachnospiracea (groups UCG-002 and UCG-006), and Flexilinea 14 d before calving, and increased RA of Streptococcus 21 d after calving compared with control cows. However, changes in the ruminal microbiota were more drastic across days relative to calving than as influenced by the dietary treatment, and the effect of LY in the colon was milder than in the rumen. The ruminal RA of several genera was associated with postcalving DMI, and that of Gastranaerophilales was the only order positively associated with milk yield. Several genera were positively correlated with feed efficiency, with Clostridiales (unclassified) being the only genus negatively associated with feed efficiency. In the colon, Prevotellaceae (group Ga6A1) was the only genus positively associated with feed efficiency. The ruminal RA of Prevotella 7 and Ruminobacter 14 d precalving was negatively correlated with dry matter intake and milk yield postcalving. The RA of Parabacteroides in the colon 14 d before calving was negatively correlated with milk yield, whereas the RA of Eggerthellaceae (unclassified) and Erysipelotrichaceae (groups c and unclassified) were positively correlated with feed efficiency. Interestingly, LY supplementation doubled the RA of Eggerthellaceae (unclassified) in the colon. It is concluded that microbial diversity in the rumen experiences a transient reduction after calving, whereas in the colon, the reduction is maintained at least until 21 d in milk. Most of the effects of LY on rumen microbiota were observed before calving, whereas in the colon, LY effects were more moderate but consistent and independent of the stage of production. The microbial community of the rumen after calving is more associated with feed intake, milk yield, and feed efficiency than that of the colon. However, the colon microbiota before calving is more associated with feed efficiency after calving than that of the rumen.

A new approach to obtain pure and active proteins from Lactococcus lactis protein aggregates

The production of pure and soluble proteins is a complex, protein-dependent and time-consuming process, in particular for those prone-to-aggregate and/or difficult-to-purify. Although Escherichia coli is widely used for protein production, recombinant products must be co-purified through costly processes to remove lipopolysaccharide (LPS) and minimize adverse effects in the target organism. Interestingly, Lactococcus lactis, which does not contain LPS, could be a promising alternative for the production of relevant proteins. However, to date, there is no universal strategy to produce and purify any recombinant protein, being still a protein-specific process. In this context and considering that L. lactis is also able to form functional protein aggregates under overproduction conditions, we explored the use of these aggregates as an alternative source of soluble proteins. In this study, we developed a widely applicable and economically affordable protocol to extract functional proteins from these nanoclusters. For that, two model proteins were used: mammary serum amyloid A3 (M-SAA3) and metalloproteinase 9 (MMP-9), a difficult-to-purify and a prone-to-aggregate protein, respectively. The results show that it is possible to obtain highly pure, soluble, LPS-free and active recombinant proteins from L. lactis aggregates through a cost-effective and simple protocol with special relevance for difficult-to-purify or highly aggregated proteins.

Changes in gene expression in the rumen and colon epithelia during the dry period through lactation of dairy cows and effects of live yeast supplementation

The objectives of this study were (1) to use endoscopy to collect biopsies from the rumen and colon epithelia to describe changes in gene expression in these 2 tissues as cows move from a dry to a lactation ration and (2) to evaluate the potential influence that supplementation of live yeast could exert on these 2 epithelia. Twenty-one Holstein cows were split into 2 treatments and received either 300 g/d of corn containing 1 × 10¹⁰ cfu/d of live yeast (LY; n = 10) or 300 g/d of corn with no supplementation (control; n = 11) starting 21 ± 2.6 d (average ± SD) before until 21 d after calving. At 14 ± 2.6 d before the expected calving date, and exactly at 7 and 21 d after calving, rumen and colon biopsies were obtained from each cow using an endoscope. Total RNA was extracted from rumen and colon tissues, and the expression of IL10, TNFA, TLR4, IL1B, PCNA, MKI67, SGLT1, BAX, CASP3, OCLN, CLDN4, HSPA1A, HSPB1, DEFB1, and MCT1 (the latter only in rumen samples) was quantified by quantitative PCR. Overall, fluctuations in expression of the selected genes in the colon between the 2 stages of production and the 2 treatments were smaller than those found in the rumen. In the rumen epithelium, expression of TLR4 and DEFB1 was greatest before calving, with LY cows having a greater expression of TLR4 than control cows. Similarly, expression of IL10 was greatest in LY cows before calving. Expression of TNFA in the rumen epithelium of control cows was lowest at 21 DIM but in LY cows was kept steady among production stages. The expression of PCNA and MKI67 in the rumen epithelium was greatest at 7 DIM, indicating a high proliferation rate of this epithelium after calving. In the colon mucosa, expression of TLR4 and DEFB1 was greater than in the rumen, and DEFB1 expression was greater in LY cows than in control cows. The use of an endoscope allowed us to study the dynamics of rumen epithelium adaptation to increased supply of concentrate after calving, consisting of increased epithelia remodeling, reduction of the TLR4, and increased IL10 expression. Furthermore, the rumen epithelium of dry cows responded rapidly to live yeast, with changes in the expression of genes involved in the immune response becoming evident after 7 d of exposure to yeast. The expression of genes related to the immune response (mainly TLR4 and DEFB1) in the colon mucosa was greater than in the rumen, and the expression of DEFB1 was further stimulated by live yeast. It is concluded that the use of an endoscope allows the study of gene expression patterns in the rumen and hindgut epithelia. We report marked changes in the rumen wall and more modest changes in the colon when transitioning from a dry to a lactation ration. Furthermore, supplementation of live yeast fostered and increased expression of genes regulating inflammation and epithelial barrier in the rumen, and in the colon it increased the expression of DFEB1 coding for an antimicrobial peptide.

Short communication: Comparison of pH, volatile fatty acids, and microbiome of rumen samples from preweaned calves obtained via cannula or stomach tube

The objective of this study was to compare rumen samples from young dairy calves obtained via a stomach tube (ST) or a ruminal cannula (RC). Five male Holstein calves (46±4.0 kg of body weight and 11±4.9 d of age) were ruminally cannulated at 15 d of age. Calves received 4 L/d of a commercial milk replacer (25% crude protein and 19.2% fat) at 12.5% dry matter, and were provided concentrate and chopped oats hay ad libitum throughout the study (56 d). In total, 29 paired rumen samples were obtained weekly throughout the study in most of the calves by each extraction method. These samples were used to determine pH and volatile fatty acids (VFA) concentration, and to quantify Prevotella ruminicola and Streptococcus bovis by quantitative PCR. Furthermore, a denaturing gradient gel electrophoresis was performed on rumen samples harvested during wk 8 of the study to determine the degree of similarity between rumen bacteria communities. Rumen pH was 0.30 units greater in ST compared with RC samples. Furthermore, total VFA concentrations were greater in RC than in ST samples. However, when analyzing the proportion of each VFA by ANOVA, no differences were found between the sampling methods. The quantification of S. bovis and P. ruminicola was similar in both extraction methods, and values obtained using different methods were highly correlated (R(2)=0.89 and 0.98 for S. bovis and P. ruminicola, respectively). Fingerprinting analysis showed similar bacteria band profiles between samples obtained from the same calves using different extraction methods. In conclusion, when comparing rumen parameters obtained using different sampling techniques, it is recommended that VFA profiles be used rather than total VFA concentrations, as total VFA concentrations are more affected by the method of collection. Furthermore, although comparisons of pH across studies should be avoided when samples are not obtained using the same sampling method, the comparison of fingerprinting of a bacteria community or a specific rumen bacterium is valid.