Effects of partially replacing dietary corn with molasses, condensed whey permeate, or treated condensed whey permeate on ruminal microbial fermentation

Partial replacement of soybean meal with microalgae biomass on in vitro ruminal fermentation may reduce ruminal protein degradation

The objective of this study was to evaluate the effects of partially replacing soybean meal (SBM) with algal sources on in vitro ruminal fermentation. Using 6 fermenters in a 3 × 3 replicated Latin square with 3 periods of 10 d each, we tested 3 treatments: a control diet (CRT) with SBM at 17.8% of the diet dry matter (DM); and 50% SBM biomass replacement with either Chlorella pyrenoidosa (CHL); or Spirulina platensis (SPI). The basal diet was formulated to meet the requirements of a 680-kg Holstein dairy cow producing 45 kg/d of milk with 3.5% fat and 3% protein. All diets had a similar nutritional composition (16.0% CP; 34.9% NDF; 31.0% starch, DM basis) and fermenters were provided with 106 g DM/d split into 2 portions. After 7 d of adaptation, samples were collected for 3 d of each period for analyses of ruminal fermentation at 0, 1, 2, 4, 6, and 8 h after morning feeding for evaluation of the ruminal fermentation kinetics. For the evaluation of the daily production of total metabolites and for the evaluation of nutrient degradability, samples from the effluent containers were collected daily. Statistical analysis was performed with the MIXED procedure of SAS with treatment, time, and their interactions considered as fixed effects; day, square, and fermenter were considered as random effects. Orthogonal contrasts (CRT vs. algae; and CHL vs. SPI) were used to depict the treatment effect, and significance was declared when P ≤ 0.05. Fermenters that received algae-based diets had a greater propionate molar concentration and molar proportion when compared with the fermenters fed CRT diets. In addition, those algae-fed fermenters had lower branched short-chain fatty acids (BSCFA) and isoacids (IA), which are biomarkers of ruminal protein degradation, along with lower ammonia (NH3-N) concentration and greater nonammonia nitrogen (NAN). When contrasting with fermenters fed SPI-diets, fermenters fed based CHL-diets had a lower molar concentration of BSCFA and IA, along with lower NH3-N concentration and flow, and greater NAN, bacterial nitrogen flow, and efficiency of nitrogen utilization. Those results indicate that CHL protein may be more resistant to ruminal degradation, which would increase efficiency of nitrogen utilization. In summary, partially replacing SBM with algae biomass, especially with CHL, is a promising strategy to improve the efficiency of nitrogen utilization, due to the fact that fermenters fed CHL-based diets resulted in a reduction in BSCFA and IA, which are markers of protein degradation, and it would improve the efficiency of nitrogen utilization. However, further validation using in vivo models are required.

Concentrate supplementation improves cold-season environmental fitness of grazing yaks: responsive changes in the rumen microbiota and metabolome

Yak (Bos grunniens) is an important economic animal species on the Qinghai-Tibet Plateau. Yaks grazed in the cold season often suffer from nutritional stress, resulting in low production performance. This situation can be improved by properly feeding the grazing yaks in the cold season; however, there is still little information about the effect of different feeding levels on the intestinal microflora and metabolites of yaks. Therefore, this study aimed to explore the effect of feeding different doses of concentrate supplements on rumen bacterial communities and metabolites in grazing yaks during the cold season. Feed concentrate supplementation significantly improved the production performance and rumen fermentation status of grazing yaks during the cold season, and switched the type of ruminal fermentation from acetic acid fermentation to propionic acid fermentation. Ruminal fermentation parameters and ruminal bacterial abundance correlated strongly. At the phylum level, the abundance of Firmicutes increased with increasing concentrate supplementation, while the opposite was true for Bacteroidota. At the genus level, the abundance of Christensenellaceae_R-7_group, NK4A214_group, Ruminococcus, norank_f__Eubacterium_coprostanoligenes_group, norank_f__norank_o__ Clostridia_UCG-014, Lachnospiraceae_NK3A20_group, Acetitomaculum, and Family_XIII_AD3011_group increased with increasing concentrate supplementation, while the abundance of Rikenellaceae_RC9_gut_ group decreased. Dietary concentrate supplementation altered the concentration and metabolic mode of metabolites in the rumen, significantly affecting the concentration of metabolites involved in amino acid and derivative metabolism (e.g., L-aspartic acid, L-glutamate, and L-histidine), purine metabolism (e.g., guanine, guanosine, and hypoxanthine), and glycerophospholipid metabolism (e.g., phosphatidate, phosphatidylcholine, and phosphocholine), and other metabolic pathways. The strong correlation between yak rumen microorganisms and metabolites provided a more comprehensive understanding of microbial community composition and function. This study showed significant changes in the composition and abundance of bacteria and metabolites in the rumen of cool season grazing yaks fed with concentrate supplements. Changes in ruminal fermentation parameters and metabolite concentration also showed a strong correlation with ruminal bacterial communities. These findings will be helpful to formulate supplementary feeding strategies for grazing yaks in the cold season from the perspective of intestinal microorganisms.

The Impact of Biotechnologically Produced Lactobionic Acid in the Diet of Lactating Dairy Cows on Their Performance and Quality Traits of Milk

Dairy processing is one of the most polluting sectors of the food industry as it causes water pollution. Given considerable whey quantities obtained via traditional cheese and curd production methods, manufacturers worldwide are encountering challenges for its rational use. However, with the advancement in biotechnology, the sustainability of whey management can be fostered by applying microbial cultures for the bioconversion of whey components such as lactose to functional molecules. The present work was undertaken to demonstrate the potential utilization of whey for producing a fraction rich in lactobionic acid (Lba), which was further used in the dietary treatment of lactating dairy cows. The analysis utilizing high-performance liquid chromatography with refractive index (HPLC-RID) detection confirmed the abundance of Lba in biotechnologically processed whey, corresponding to 11.3 g L^-1. The basic diet of two dairy cow groups involving nine animals, Holstein Black and White or Red breeds in each, was supplemented either with 1.0 kg sugar beet molasses (Group A) or 5.0 kg of the liquid fraction containing 56.5 g Lba (Group B). Overall, the use of Lba in the diet of dairy cows during the lactation period equal to molasses affected cows' performances and quality traits, especially fat composition. The observed values of urea content revealed that animals of Group B and, to a lesser extent, Group A received a sufficient amount of proteins, as the amount of urea in the milk decreased by 21.7% and 35.1%, respectively. After six months of the feeding trial, a significantly higher concentration of essential amino acids (AAs), i.e., isoleucine and valine, was observed in Group B. The percentage increase corresponded to 5.8% and 3.3%, respectively. A similar trend of increase was found for branched-chain AAs, indicating an increase of 2.4% compared with the initial value. Overall, the content of fatty acids (FAs) in milk samples was affected by feeding. Without reference to the decrease in individual FAs, the higher values of monounsaturated FAs (MUFAs) were achieved via the supplementation of lactating cows' diets with molasses. In contrast, the dietary inclusion of Lba in the diet promoted an increase in saturated FA (SFA) and polyunsaturated FA (PUFA) content in the milk after six months of the feeding trial.

The Effects of Incremental Doses of Aflatoxin B1 on In Vitro Ruminal Nutrient Digestibility and Fermentation Profile of a Lactating Dairy Cow Diet in a Dual-Flow Continuous Culture System

Aflatoxin B₁ (AFB₁) is a mycotoxin known to impair human and animal health. It is also believed to have a deleterious effect on ruminal nutrient digestibility under in vitro batch culture systems. The objective of this study was to evaluate the effects of increasing the dose of AFB₁ on ruminal dry matter and nutrient digestibility, fermentation profile, and N flows using a dual-flow continuous culture system fed a diet formulated for lactating dairy cows. Eight fermenter vessels were used in a replicated 4 × 4 Latin square design with 10 d periods (7 d adaptation and 3 d sample collection). Treatments were randomly applied to fermenters on diet DM basis: (1) 0 μg of AFB₁/kg of DM (Control); (2) 50 μg of AFB₁/kg of DM (AF50); (3) 100 μg of AFB₁/kg of DM (AF100); and (4) 150 μg of AFB₁/kg of DM (AF150). Treatments did not affect nutrient digestibility, fermentation, and N flows. Aflatoxin B₁ concentration in ruminal fluid increased with dose but decreased to undetectable levels after 4 h post-dosing. In conclusion, adding incremental doses of AFB₁ did not affect ruminal fermentation, digestibility of nutrients, and N flows in a dual-flow continuous culture system fed diets formulated for lactating dairy cows.

Improvement of Rumen Fermentation Efficiency Using Different Energy Sources: In Vitro Comparison between Buffalo and Cow

During haymaking and ensilage, a significant loss of sugars occurs. The addition of a total mixed ratio (TMR) with a liquid feed might provide promptly utilisable energy and recover the nutrients lost during the conservation. Interesting results were already obtained by including liquid feed in a TMR in a dairy cow. However, the possibility to also utilize them in Italian Mediterranean buffalo is not yet supported by data. This study aimed to evaluate the in vitro fermentation characteristics and kinetics of different types of liquid feed, utilising bovine and buffalo rumen liquor as inocula. TMR supplemented with 0.025 g of four different liquid feeds was incubated with the TMR as control with buffalo and bovine rumen fluid using in vitro gas production technique. Considering bovine inoculum, all the experimental diets showed lower organic matter degradability and higher volatile fatty acid production than control TMR, while with buffalo rumen liquor, significant differences were observed between experimental and control diets in terms of gas production and fermentation kinetics. The tested liquid feeds can have different fermentation patterns depending on their ingredients and compositions. Supplementing liquid feeds to a standard diet seems to provide a source of energy that improves fermentation. No negative effects were observed on the in vitro fermentation at the dosage utilised.