Fonseca M. Investigating variability of craft microbreweries spent grains for classification and incorporation into precision diet formulation through multivariate analyses

Alternative feedstuffs offer a cost-effective and sustainable option for livestock nutrition, playing a crucial role in niche market development. Brewer's spent grains (BSG), a byproduct of the expanding craft microbrewery industry, are a particularly promising feed source due to their availability and nutrient content. However, variability in BSG composition poses challenges for their effective incorporation into precision diet formulations. This study aimed to evaluate the variability in the nutrient composition of BSG from craft microbreweries and classify them for precision diet formulation using multivariate analyses. BSG samples from 29 craft microbreweries were collected and analysed for their nutrient composition using wet chemistry methods. Principal components analysed included crude protein (CP), ash and protein corrected neutral detergent fiber (apNDFom), non-fibrous carbohydrates (NFC), and ether extract (EE). Principal component analysis (PCA) was employed to identify the most significant nutrient variations, and hierarchical clustering of the principal components was used to group the samples into four distinct clusters. These clusters were further evaluated through in vitro fermentation tests, assessing gas production, digestibility, and fermentation characteristics. Statistical analyses were conducted using R software. The principal components (energy (PC1) and protein (PC2) were the primary factors driving BSG variability. Hierarchical clustering produced four distinct feed clusters, which showed significant differences (P < 0.05) in fermentation profiles, The apNDFom digestibility varied across clusters, with energy-dense feeds (higher and lower energy grains) demonstrating higher digestibility (P < 0.05). The third cluster (CL3), characterized by low protein content, had significantly lower NH3-N concentrations after fermentation (P < 0.05). Regarding gas and volatile fatty acids (VFA) production, clusters exhibited significant differences (P < 0.05) compared to an alfalfa standard, highlighting the diverse fermentation characteristics of BSG. The variability in energy and protein content among BSG samples results in distinct fermentation profiles, which can influence animal performance and environmental outcomes. These findings emphasize the importance of classifying BSG and incorporating precision formulation to mitigate adverse effects and maximize the benefits of this alternative feedstuff.

Effect of Acacia mearnsii forage or tannin extract on rumen dry matter and crude protein degradation

This study investigated rumen degradation kinetics of dry matter (DM) and crude protein (CP) in compound feed with different tannin extract inclusions and Acacia mearnsi forage (AMF) relative to dairy feeds (perennial ryegrass+white clover mixture pasture, maize silage, lucerne hay and Themeda triandra hay). The compound feed had 0.75%, 1.5% and 3% tannins extract inclusions while the control was a commercial compound feed. Triplicates of each feed per incubation period were incubated in two fistulated Jersey cows for 0, 6, 24, 48, 72, 96 and 120 h, resulting in six replicates per feed. Tannin extract inclusions in compound feed only affected (p < 0.05) the (a) fraction, degradation rate and potential degradability (PD) for DM degradation, and affected (p < 0.05) the (a) and (b) fractions, as well as PD for CP degradation. The (a) fraction and degradation rate for DM degradation changed linearly (p < 0.05). The (a) fraction, PD and effective degradability (ED) of DM degradation changed quadratically (p < 0.05). Except for the degradation rate, the feed type affected (p < 0.05) the degradation parameters in both DM and CP degradations. For DM and CP degradations, (a) fraction was similarly the least in Themeda triandra hay and AMF but similarly the highest in maize silage, perennial ryegrass+white clover mixture pasture and lucerne hay. The (b) fraction was the least in AMF for both DM and CP degradations but the highest for pasture's DM degradation and similarly the highest in maize silage, lucerne hay and T. triandra hay for CP degradation. The PD was the least in AMF for both DM and CP degradations and similarly the highest in pasture DM but similarly the highest in perennial ryegrass+white clover mixture pasture, maize silage and lucerne hay for CP degradation. Furthermore, the ED was the lowest in AMF and the highest for perrenial ryegrass + white clover mixture pasture for DM degradation and same trend was observed for CP degradation whereby perrenial ryegrass + white clover mixture pasture, maize silage and lucerne had the highest ED. Digestible undegraded protein was the highest in AMF and similarly the least in dairy feeds. Tannin source inclusion in ruminant diets should be moderate to prevent rumen DM or CP degradation limitation.

Essential Oils as In Vitro Ruminal Fermentation Manipulators to Mitigate Methane Emission by Beef Cattle Grazing Tropical Grasses

There is increasing pressure to identify natural feed additives to mitigate methane emissions from livestock systems. Our objective was to investigate the effects of essential oils (EO) extracts star anise (Illicium verum), citronella (Cymbopogon winterianus), clove bud (Eugenia caryophyllus), staigeriana eucalyptus (Eucalyptus staigeriana), globulus eucalyptus (Eucalyptus globulus), ginger (Zingiber officinale), ho wood (Cinnamomum camphora), melaleuca (Melaleuca alternifolia), oregano (Origanum vulgare) and white thyme (Thymus vulgaris) on in vitro methane emissions from four rumen-cannulated Nellore cattle grazing a tropical grass pasture as inoculum donors. The semi-automated gas production technique was used to assess total gas production, dry matter degradability, partitioning factor, ammoniacal nitrogen, short-chain fatty acids and methane production. All essential oils were tested in four doses (0, 50, 250 and 500 mg/L) in a randomized block design, arranged with four blocks, 10 treatments, four doses and two replicates. Within our study, oregano and white Thyme EO reduced net methane production at 250 mg/L, without affecting substrate degradation. Essential oils from oregano and white thyme have the potential to modify ruminal fermentation and suppress rumen methanogenesis without negative effects on feed digestibility, indicating promise as alternatives to ionophores for methane reduction in beef cattle.

Tannin-rich forage as a methane mitigation strategy for cattle and the implications for rumen microbiota

Context Methane from ruminant livestock systems contributes to the greenhouse effect on the environment, which justifies the adoption of novel feed strategies that mitigate enteric emissions. Aims We investigated the effects of the condensed tannin (CT)-rich legumes Flemingia macrophylla, Leucaena leucocephala, Stylosanthes guianensis, Gliricidia sepium, Cratylia argentea, Cajanus cajan, Desmodium ovalifolium, Macrotyloma axillare, Desmodium paniculatum and Lespedeza procumbens on in vitro methane emissions and rumen microbiota for beef cattle. Methods Four rumen-cannulated Nellore cattle grazing a tropical grass pasture were used as inoculum donors. Key results Real-time quantitative polymerase chain reaction analysis revealed that the abundance of Ruminococcus flavefaciens, methanogenic archaea and protozoa populations were reduced (P £ 0.05), whereas total ruminal bacteria were enhanced in the presence of CT. Our study also revealed a positive (P £ 0.05) relationship between CT and Fibrobacter succinogenes abundance. Reactive CT from L. leucocephala, D. paniculatum and L. procumbens resulted in decreased (P £ 0.05) isoacid content and methane production. Conclusions L. leucocephala, D. paniculatum and L. procumbens have the potential to suppress rumen methanogenesis. However, in vitro fermentation of L. leucocephala resulted in greater (P £ 0.05) degradability percentages than the other two species. Implications CT in legume species will have potential as part of an overall nutritional strategy to manipulate rumen microbiota and mitigate enteric methanogenesis in livestock production systems.