Dietary fat sources affect feed intake, digestibility, rumen microbial populations, energy partition and methane emissions in different beef cattle genotypes

Compilations and updates on residual feed intake in sheep

The increasing global demand for food and the strong effect of climate change have forced animal science to advance regarding new methods of selection in search of more efficient animals in production systems. Feed consumption represents more than 70% of the costs of sheep farms, and more efficient animals can increase the farmers' profitability. One of the main measures of feed efficiency is estimated residual feed intake (RFI), created in 1963 by Robert Koch for estimation in cattle and later adapted for sheep. Animals with negative RFI values (RFI-) are more efficient than animals with positive values (RFI+), with influence on the variables of performance, carcass quality and production of enteric gases. The RFI is the most common and accepted metric of the feed efficiency trait for genetic selection, since it is independent of growth traits, unlike the feed conversion ratio. The purpose of this review article was to present updated literature information on the relationship of RFI estimates with performance measures, molecular markers, greenhouse gas production and feed efficiency, the technical aspects and physiological basis of metabolic in sheep.

Effects of Palm Oil Deodorizer Distillate on the Ruminal Environment of Sheep

This study aimed to assess the impact of palm oil deodorizer distillate (POD) on the ruminal environment, including (i) microbial community, (ii) ruminal degradability, and (iii) apparent digestibility in sheep. The data used were derived from twenty rumen-cannulated sheep fed five isoproteic and isofiber diets based on elephant grass (Pennisetum purpureum Schum. cv. Roxo) silage supplemented with 0, 25, 50, 75, or 100 g kg-1 POD on a dry matter (DM) basis. Rumen fluid samples were collected three hours after feeding directly from the ventral sac of the rumen via a cannula and then subjected to DNA extraction, which was subsequently used for 16S rDNA amplification, followed by sequencing and diversity analysis. In this study, the microbial diversity was dominated by Bacteroidetes and Firmicutes, followed by Euryarchaetoa, Actinobacteria, and Tenericutes, in the ruminal environment, and was slightly modified when supplemented with the POD up to 100 g/kg (10%), leading to only a slight decrease in the diversity index. The ruminal degradability, ruminal fermentation parameters, and apparent digestibility were slightly compromised by the inclusion of up to 25 g of POD per kg of DM, and larger inclusions interfered with the ruminal degradability of fibrous fractions and the apparent digestibility of dry matter. This lipid supplement showed good results for feeding sheep and is an inexpensive and abundant alternative in the regional market.

New Implications of Metabolites and Free Fatty Acids in Quality Control of Crossbred Wagyu Beef during Wet Aging Cold Storage

Efficient cold-chain delivery is essential for maintaining a sustainable global food supply. This study used metabolomic analysis to examine meat quality changes during the "wet aging" of crossbred Wagyu beef during cold storage. The longissimus thoracic (Loin) and adductor muscles (Round) of hybrid Wagyu beef, a cross between the Japanese Black and Holstein-Friesian breeds, were packaged in vacuum film and refrigerated for up to 40 days. Sensory evaluation indicated an increase in the umami and kokumi taste owing to wet aging. Comprehensive analysis using gas chromatography-mass spectrometry identified metabolite changes during wet aging. In the Loin, 94 metabolites increased, and 24 decreased; in the Round, 91 increased and 18 decreased. Metabolites contributing to the umami taste of the meat showed different profiles during wet aging. Glutamic acid increased in a cold storage-dependent manner, whereas creatinine and inosinic acid degraded rapidly even during cold storage. In terms of lipids, wet aging led to an increase in free fatty acids. In particular, linoleic acid, a polyunsaturated fatty acid, increased significantly among the free fatty acids. These results provide new insight into the effects of wet aging on Wagyu-type beef, emphasizing the role of free amino acids, organic acids, and free fatty acids generated during cold storage.

Ensiling Cyanide Residue and In Vitro Rumen Fermentation of Cassava Root Silage Treated with Cyanide-Utilizing Bacteria and Cellulase

Cyanide is a strong toxin in many tropical forage plants that can negatively affect ruminants. The aim of this study is to determine the cyanide removal efficiency, silage quality, and in vitro rumen fermentation of fresh cassava roots ensiled without an additive (control) and with Acremonium cellulase (AC), two cyanide-utilizing bacterial inoculants (Enterococcus feacium KKU-BF7 (BF7) and E. gallinarum KKU-BC10 (BC10)), and their combinations (BF7 + BC10, AC + BF7, AC + BC10 and AC + BF7 + BC10). A completely randomized design was used with eight treatments × four small-scale silo replicates. Additionally, extra silage samples (seven silos/treatment for individually opening after 0, 1, 3, 5, 7, 15, and 30 days of ensiling) were added to observe the changes in the total cyanide concentration and pH value. The fresh cassava root contained an optimal number of lactic acid bacteria (105 colony forming units/g fresh matter), and the contents of dry matter (DM) and total cyanides were 30.1% and 1304 mg/kg DM, respectively. After 30 days of ensiling, all silages demonstrated a low pH (<3.95; p < 0.01). Cyanide content ranged from 638 to 790 mg/kg DM and was highest in the control (p < 0.01). The addition of BF7 + BC10 increased the crude protein (CP) content (p < 0.01). The addition of AC decreased the fibrous contents (p < 0.01). The control had less acetic acid and propionic acid contents (p < 0.01) and a greater butyric acid content (p < 0.01). However, the degrees of in vitro DM digestibility (IVDMD) and gas production were similar among treatments. Methane production ranged between 29.2 and 33.3 L/kg IVDMD (p < 0.05), which were observed in the AC + BC10 and BF7 + BC10 treatments, respectively. Overall, our results suggested that the cyanide removal efficiency after 30 days of ensiling with good-quality cassava-root silage was approximately 39% of the initial value. The enterococci inoculants and/or AC could improve the ensiling process and cyanide removal efficiency (increasing it to between 47 and 51% of the initial value). The novel enterococci inoculants (BF7 + BC10) were associated with a decreased cyanide content and an increased CP content. They appeared to promote the methanogenesis potential of the cassava root silage. More research is required to validate the use of cyanide-utilizing bacterial inoculants in cyanogenetic plants, bioenergy fermentation, and livestock.

Production of Hydroxy Fatty Acids, Precursors of γ-Hexalactone, Contributes to the Characteristic Sweet Aroma of Beef

Aroma is an essential factor for meat quality. The meat of Japanese Black cattle exhibits fine marbling and a rich and sweet aroma with a characteristic lactone composition. The mechanism of lactone formation associated with beef aroma has not been elucidated. In this study, we examined the precursors of γ-hexalactone, an indicator of the sweet aroma of beef and identified the mechanism underlying γ-hexalactone production. A low-temperature vacuum system was used to prepare beef tallow from Japanese Black cattle and Holstein cattle. The odor components were identified using headspace–gas chromatography. The analysis revealed that γ-hexalactone, γ-dodecalactone, δ-tetradecalactone, and δ-hexadecalactone were present as sweet aroma components of beef tallow prepared from marbling and muscle. Since we previously reported that γ-hexalactone formation correlates with linoleic acid content in beef, we analyzed ten oxidized fatty acids derived from linoleic acid by liquid chromatography–triple quadrupole mass spectrometry and detected two hydroxy-octadecadienoic acids (9S-HODE and 13S-HODE) in beef tallow. Significant differences in arachidonic acid 15-lipoxygenase and cyclooxygenase protein expression levels among subcutaneous fat, intramuscular fat, and muscle tissue were observed. Our results suggest that the combination of linoleic acid and the expression of lipid oxidase derived from beef muscle and intramuscular fat produce hydroxy fatty acids that result in a sweet aroma.

Characterization of Green Manure Sunn Hemp Crop Silage Prepared with Additives: Aerobic Instability, Nitrogen Value, and In Vitro Rumen Methane Production

Sunn hemp (SH, Crotalaria juncea, L.) is a tropical multiple-purpose legume. The green manure SH (GMSH) crop might display protein ecology in sustaining ruminants; however, its silage features remain unclear. To efficiently prepare GMSH crop silage, additive treatments consisting of control (no additive, CON), molasses (MO), Acremonium cellulase (AC), and Lactobacillus casei TH14 strain inoculant (TH14) were implemented using a completely randomized design. Repeated measurements were done after silage (AE conditions) in a small-scale silo system for 120 days and after aerobic instability (AE + AIS conditions). Briefly, ensiling loss and aerobic stability ranged from 150 to 175 g/kg and 8.3 to 104 days, respectively. In AE conditions, the pH ranged from 4.33 to 5.74, and MO or AC was desirable (p < 0.01) for lactic acid fermentation. AC reduced the fiber contents. MO increased soluble non-protein nitrogen by decreasing insoluble nitrogen. TH14 increased the ammonia nitrogen level and in vitro methane production. In AE + AIS conditions, AC led to more air damage to the chemical compositions and reduced digestibility in vitro. The results show that an optimization of additives could effectively modify GMSH crop silage to make it a good protein roughage source; however, more studies are required for effectively feeding ruminants.

Transcriptome analysis reveals the potential roles of long non-coding RNAs in feed efficiency of chicken

Feed efficiency is an important economic trait and reduces the production costs per unit of animal product. Up to now, few studies have conducted transcriptome profiling of liver tissue in feed efficiency-divergent chickens (Ross vs native breeds). Also, molecular mechanisms contributing to differences in feed efficiency are not fully understood, especially in terms of long non-coding RNAs (lncRNAs). Hence, transcriptome profiles of liver tissue in commercial and native chicken breeds were analyzed. RNA-Seq data along with bioinformatics approaches were applied and a series of lncRNAs and target genes were identified. Furthermore, protein-protein interaction network construction, co-expression analysis, co-localization analysis of QTLs and functional enrichment analysis were used to functionally annotate the identified lncRNAs. In total, 2,290 lncRNAs were found (including 1,110 annotated, 593 known and 587 novel), of which 53 (including 39 known and 14 novel), were identified as differentially expressed genes between two breeds. The expression profile of lncRNAs was validated by RT-qPCR. The identified novel lncRNAs showed a number of characteristics similar to those of known lncRNAs. Target prediction analysis showed that these lncRNAs have the potential to act in cis or trans mode. Functional enrichment analysis of the predicted target genes revealed that they might affect the differences in feed efficiency of chicken by modulating genes associated with lipid metabolism, carbohydrate metabolism, growth, energy homeostasis and glucose metabolism. Some gene members of significant modules in the constructed co-expression networks were reported as important genes related to feed efficiency. Co-localization analysis of QTLs related to feed efficiency and the identified lncRNAs suggested several candidates to be involved in residual feed intake. The findings of this study provided valuable resources to further clarify the genetic basis of regulation of feed efficiency in chicken from the perspective of lncRNAs.

Transcriptome Analysis Identifies Candidate Genes and Pathways Associated With Feed Efficiency in Hu Sheep

In the genetic improvement of livestock and poultry, residual feed intake (RFI) is an important economic trait. However, in sheep, the genetic regulatory mechanisms of RFI are unclear. In the present study, we measured the feed efficiency (FE)-related phenotypes of 137 male Hu lambs, and selected six lambs with very high (n = 3) and very low (n = 3) RFI values and analyzed their liver transcriptomes. A total of 101 differentially expressed genes were identified, of which 40 were upregulated and 61 were downregulated in the low-RFI group compared with that in the high-RFI group. The downregulated genes were mainly concentrated in immune function pathways, while the upregulated genes were mainly involved in energy metabolism pathways. Two differentially expressed genes, ADRA2A (encoding adrenoceptor alpha 2A) and RYR2 (ryanodine receptor 2), were selected as candidate genes for FE and subjected to single nucleotide polymorphism scanning and association analysis. Two synonymous mutations, ADRA2A g.1429 C > A and RYR2 g.1117 A > C, were detected, which were both significantly associated with the feed conversion rate. These findings provide a deeper understanding of the molecular mechanisms regulating FE, and reveal key genes and genetic variants that could be used to genetically improve FE in sheep.

Enteric methane emissions, energy partitioning, and energetic efficiency of zebu beef cattle fed total mixed ration silage

Objective

The main objective of this study was to evaluate the effect of different feeding levels of a total mixed ration silage-based diet on feed intake, total tract digestion, enteric methane emissions, and energy partitioning in two beef cattle genotypes.

Methods

Six mature bulls (three Thai natives, and three Thai natives - Charolais crossbreeds) were assigned in a replicated 3×3 Latin square design, with cattle breed genotype in separate squares, three periods of 21 days, and three energy feeding above maintenance levels (1.1, 1.5, and 2.0 MEm, where MEm is metabolizable energy requirement for maintenance). Bulls were placed in a metabolic cage equipped with a ventilated head box respiration system to evaluate digestibility, record respiration gases, and determine energy balance.

Results

Increasing the feeding level had no significant effect on digestibility but drastically reduced the enteric methane emission rate (p<0.05). Increasing the feeding level also significantly increased the energy retention and utilization efficiency (p<0.01). The Thai native cattle had greater enteric methane emission rate, digestibility, and energy utilization efficiency than the Charolais crossbred cattle (p<0.05). The daily metabolizable energy requirement for maintenance in Thai native cattle (388 kJ/kg BW^0.75, where BW^0.75 is metabolic body weight) was 15% less than that in Charolais crossbred cattle (444 kJ/kg BW^0.75).

Conclusion

Our results suggested that the greater feeding level in zebu beef cattle fed above maintenance levels resulted in improved energy retention and utilization efficiency because of the reduction in enteric methane energy loss. The results also indicated higher efficiency of metabolisable energy utilization for growth and a lower energy requirement for maintenance in Bos indicus than in Bos taurus.