Ruminal Volatile Fatty Acids Research Articles

Effect of substituting steam-flaked corn for course ground corn on in vitro digestibility, average daily gain, serum metabolites and ruminal volatile fatty acids, and bacteria diversity in growing yaks

Yaks are well adapted to the Qinqhai-Tibetan Plateau and, traditionally, only grazed natural pasture all year without supplements. Today, however, yaks are also raised in feedlots; consequently, more information is needed in choosing optimal feeding regimes. This study examined the effects of substituting steam-flaked corn (SFC) for coarse ground corn (CGC) on average daily gain (ADG), in vitro true digestibility (IVTD), concentrations of ruminal volatile fatty acids (VFAs) and serum metabolites, and rumen bacterial diversity of growing yaks. Twenty-one, 2-year-old male yaks (138 ± 37.3 kg) were divided randomly into 3 groups (n = 7 per group) and received a total mixed ration (TMR) for 143 days. The TMR contained 446 g corn per kg dry matter (DM), but the ratio of CGC: SFC differed among the three groups as: 1) 100:0 (SFC0), 2) 50:50 (SFC50), and 3) 0:100 (SFC100). To maintain conditions similar to the feedlots, the yaks were fed as a group and feed intake was recorded daily. The yaks were weighed on 6 occasions during the study and ADG was calculated for each yak from the regression equation of body weight (BW) on days of treatment. On the morning of d 144 before feed was offered, jugular vein blood was collected to measure the concentrations of serum metabolites, and rumen contents were collected to determine ruminal VFAs, fermentation parameters and bacterial diversity. The daily dry matter intake (DMI) averaged between 6.08 and 6.15 kg per yak for the three dietary treatments and the IVTD increased with an increase in SFC (P < 0.05). The ADG was higher (P < 0.05) by 13.2% (812 vs 717 g/d) in the SFC100 group than in the SFC0 group while the ratio of the average daily DMI per yak to the average ADG per yak was lowest numerically for the SFC100 group (7.51), followed by the SFC50 group (8.46) and then the SFC0 group (8.66). The serum concentrations of alkaline phosphatase (ALP), serum urea-N, and triglycerides (TG) decreased (P < 0.05) but of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and total cholesterol (TC) increased (P < 0.05) with an increasing proportion of dietary SFC. The greater serum concentration of LDH and lesser concentration of serum urea-N suggests that the SFC50 and SFC100 groups were proliferating cells at a faster rate and depositing more protein in muscle tissue than the SFC0 group, as the ADG increased with an increase in the level of dietary SFC. The ruminal concentrations of VFAs increased and of NH3-N decreased with an increase in the proportion of SFC. The rumen bacterial diversity did not differ among dietary groups; Bacteroidetes and Firmicutes were the dominant phyla and Prevotella and Succiniclasticum were the dominant genera in all dietary treatments. These results demonstrated that increasing the proportion of SFC could improve IVTD, ruminal concentration of VFAs, ADG and the group DMI to ADG ratio.

Effects of rumen-protected methionine supplementation on production performance, apparent digestibility, blood parameters, and ruminal fermentation of lactating Holstein dairy cows.

This study aimed to evaluate the effects of reducing dietary CP and supplementing rumen protected-methionine (RPM) on production performance, blood parameters, digestibility of nutrients or ruminal fermentation in lactating Holstein dairy cows. A total of 96 lactating cows were randomly assigned to 1 of 2 treatments: a diet containing 17.3% CP without RPM (control group; CON; n = 49) or a diet containing 16.4% CP and supplemented with 15.0 g/d of RPM (treatment group; RPM; n = 47). No effect was observed in the RPM group on milk yield, milk composition and digestibility of nutrients. The results of blood parameters showed that cows in the RPM group exhibited lower blood urea nitrogen concentration than in CON group. Rumen microbial crude protein (MCP) was higher in the RPM group compared to the CON group. Ruminal volatile fatty acid (VFA) concentrations were not different between treatments except for butyrate and isovalerate, which were higher in the RPM group than the CON group 2 h after feeding. In conclusion, reducing dietary CP with RPM supplementation did not limit milk yield, milk composition or digestibility of nutrients, but could improve nitrogen utilization, synthesis of MCP and partially increase VFA production 2 h after feeding cows.

Effects of particle size and toasting of fava beans and forage source on nutrient digestibility, ruminal fermentation, and metabolizable protein supply in dairy cows.

The objective of this study was to investigate the effects of heat treatment (toasting) and particle size alterations (grinding; rolling) on nutrient utilization, ruminal fermentation, and supply of metabolizable protein (MP), and to study the interaction between processing conditions of fava beans and forage type. Six Danish Holstein dairy cows fitted with ruminal, duodenal, and ileal cannulas were used in a 6 × 4 incomplete Latin square design with 4 periods of 21-d duration. Cows were fed ad libitum with 6 experimental diets: diets high in either grass-clover silage or corn silage were combined with ground untoasted, ground toasted, or rolled untoasted fava beans. Samples of ruminal fluid, digesta from duodenum and ileum, and feces were collected, and nutrient digestibility was estimated using Cr2O3 and TiO2 as flow markers. Diets high in corn silage resulted in higher ruminal pH and higher proportion of propionate in ruminal volatile fatty acids compared with diets high in grass-clover silage. Diets high in corn silage resulted in higher apparent total-tract digestibility of crude protein and starch but lower apparent ruminal and total-tract digestibility of neutral detergent fiber compared with diets high in grass-clover silage. Rolling of fava beans decreased the in situ small intestinal disappearance of rumen-undegradable protein corrected for particle losses. Compared with grinding, rolling of fava beans reduced apparent ruminal digestibility of starch, true ruminal digestibility of organic matter, crude protein, and AA, and small intestinal digestibility of AA and starch. Grinding of fava beans increased apparent ruminal digestibility of neutral detergent fiber and reduced the proportion of propionate in ruminal volatile fatty acids compared with rolling of fava beans. In addition, rolling of fava beans had no effect on MP supply. Toasting of fava beans had no effect on in vivo nutrient digestibility except for an interaction with forage source on apparent ruminal dry matter and organic matter digestibility. Toasting of fava beans did not affect small intestinal digestion of individual and total AA, and therefore failed to increase MP supply. In conclusion, neither replacing grass-clover silage with corn silage, nor toasting nor rolling of fava beans had an effect on supply of MP.

Using probiotics to improve the utilization of chopped dried date palm leaves as a feed in diets of growing Farafra lambs.

The study determined the ability of three probiotics to improve the nutritional value of date palm leaves in diets of growing lambs. Twenty male Farafra lambs (26 ± 0.33 kg) were randomly allocated to one of four treatments (n = 6) and fed: a control or basal diet (C; 70% concentrate + 30% date palm leaves without additives) and supplemented with Bacillofort containing 2 × 1011 CFU of Bacillus subtilis/g (BAC treatment), Lacotpro containing 1 × 1012 CFU of Lactobacillus acidophilus/g (LAC treatment) or ZAD containing 6 × 108 CFU of R. albus/g (ZAD treatment) at 4 g of all additives for 150 days. As a result of this study, LAC improved (P < 0.05) growth performance and feed efficiency compared to control. Additives increased (P = 0.001) concentrations of albumin, triiodothyronine, and thyroxine, hemoglobin concentration and red blood cells and decreased (P = 0.001) globulin and urea-N. Additives increased hot carcass (P = 0.040) while BAC increased Longissimus dorsi, meat and fat without affecting water holding capacity compared to other treatments. In the metabolism experiment, BAC increased the digestibility of crude protein, while BAC and ZAD increased the digestibility of dry matter, organic matter, and neutral detergent fiber. Additives did not affect nitrogen (N) intake and urinary N; however, decreased fecal N and increased N balance compared to the control. BAC and ZAD increased ruminal volatile fatty acids concentration compared to the control. Based on our results, Lacotpro could be used to improve growth performance and feed efficiency, while Bacillofort could be used to improve meat quality of in lambs.

Different feeding strategies can affect growth performance and rumen functions in Gangba sheep as revealed by integrated transcriptome and microbiome analyses.

Due to the harsh environment in the Tibetan Plateau, traditional grazing greatly limits the growth potential of local animals and causes severe ecosystem degradation. This is an urgent issue to be solved, which requires alternative strategies for grazing animals in the Tibetan alpine pastoral livestock systems. This study aimed to investigate the effects of different feeding strategies on growth performance and ruminal microbiota-host interactions in the local breed of sheep (Gangba sheep). Thirty 9-month old Gangba sheep (n = 10 per group) were assigned to natural grazing (G), semi-grazing with supplementation (T), and barn feeding (F) groups (supplementation of concentrate and oat hay) based on body weight. At the end of the experiment (75 d), all sheep were weighed, rumen fluid was obtained from six sheep per group, and ruminal epithelium was obtained from 3 sheep per group. The results showed that: (1) Compared with the G and T groups, the F group significantly increased dry matter intake, average daily gain, and feed conversion ratio of animals. Additionally, Gangba sheep in the F group had higher concentrations of ruminal short-chain volatile fatty acids (VFAs), especially propionate and butyrate (P <0.05) than sheep in the G and T groups. (2) The principal coordinates analysis indicated a significant difference in bacterial composition among different feed strategies. More specifically, the relative abundance of propionate (unidentified F082 and Succiniclasticum) and butyrate-producing (Eubacterium_coprostanoligenes_group) genera were also observed to be increased in the F group, in which unidentified F082 was identified as a differential biomarker among the three groups according to linear discriminant analysis effect size analysis. (3) The dynamics of the rumen epithelial transcriptome revealed that ECM-receptor interactions, focal adhesion, and PI3K-Akt signaling pathways, which are critical in mediating many aspects of cellular functions such as cell proliferation and motility, were upregulated in the F group. In conclusion, under harsh conditions in the Tibetan alpine meadow, barn feeding increased ruminal VFAs concentrations (especially propionate and butyrate), which stimulated gene expression related to cell proliferation in rumen epithelium, appearing to be superior to natural grazing and semi-grazing in gaining body weight of the local Gangba sheep.

Application of 3-nitrooxypropanol and canola oil to mitigate enteric methane emissions of beef cattle results in distinctly different effects on the rumen microbial community

BackgroundThe major greenhouse gas from ruminants is enteric methane (CH4) which in 2010, was estimated at 2.1 Gt of CO2 equivalent, accounting for 4.3% of global anthropogenic greenhouse gas emissions. There are extensive efforts being made around the world to develop CH4 mitigating inhibitors that specifically target rumen methanogens with the ultimate goal of reducing the environmental footprint of ruminant livestock production. This study examined the individual and combined effects of supplementing a high-forage diet (90% barley silage) fed to beef cattle with the investigational CH4 inhibitor 3-nitrooxypropanol (3-NOP) and canola oil (OIL) on the rumen microbial community in relation to enteric CH4 emissions and ruminal fermentation.Results3-NOP and OIL individually reduced enteric CH4 yield (g/kg dry matter intake) by 28.2% and 24.0%, respectively, and the effects were additive when used in combination (51.3% reduction). 3-NOP increased H2 emissions 37-fold, while co-administering 3-NOP and OIL increased H2 in the rumen 20-fold relative to the control diet. The inclusion of 3-NOP or OIL significantly reduced the diversity of the rumen microbiome. 3-NOP resulted in targeted changes in the microbiome decreasing the relative abundance of Methanobrevibacter and increasing the relative abundance of Bacteroidetes. The inclusion of OIL resulted in substantial changes to the microbial community that were associated with changes in ruminal volatile fatty acid concentration and gas production. OIL significantly reduced the abundance of protozoa and fiber-degrading microbes in the rumen but it did not selectively alter the abundance of rumen methanogens.ConclusionsOur data provide a mechanistic understanding of CH4 inhibition by 3-NOP and OIL when offered alone and in combination to cattle fed a high forage diet. 3-NOP specifically targeted rumen methanogens and partly inhibited the hydrogenotrophic methanogenesis pathway, which increased H2 emissions and propionate molar proportion in rumen fluid. In contrast, OIL caused substantial changes in the rumen microbial community by indiscriminately altering the abundance of a range of rumen microbes, reducing the abundance of fibrolytic bacteria and protozoa, resulting in altered rumen fermentation. Importantly, our data suggest that co-administering CH4 inhibitors with distinct mechanisms of action can both enhance CH4 inhibition and provide alternative sinks to prevent excessive accumulation of ruminal H2.

Partial Substitution of Alfalfa Hay by Stevia (Stevia rebaudiana) Hay Can Improve Lactation Performance, Rumen Fermentation, and Nitrogen Utilization of Dairy Cows.

The objective of this study was to determine the effect of replacing isonitrogenous and isoenergetic basis alfalfa hay (AH) with stevia (Stevia rebaudiana) hay in dairy cow diets on nutrient digestion, milk performance, rumen fermentation, and nitrogen (N) utilization. In this study, 24 healthy Holstein lactating dairy cattle with a similar milk yield of 33.70 ± 2.75 (mean ± SD) kg, days in milk 95.98 ± 23.59 (mean ± SD) days, and body weight 587.75 ± 66.97 (mean ± SD) kg were selected and randomly allocated into three groups. The constituents of the three treatments were (1) 30.0% AH, and 0% stevia hay (SH) for the AH group; (2) 24.0% AH, and 6% SH for the 6% SH group; (3) 18.0% AH, and 12% SH for the 12% SH group. The substitution of AH with SH did not affect dry matter intake (DMI), gross energy (GE), and other nutrients intake but increased the digestibility of neutral detergent fiber (NDF) and acid detergent fiber (ADF). Compared with the AH diet, the cows fed the 6% SH diet had a higher milk yield and concentration of milk fat. Fecal and urinary nitrogen (N) were lower in cows fed a 6% SH diet than in cows fed the AH diet. Milk N secretion and milk N as a percentage of N intake were higher in cows fed a 6% SH diet than in cows fed AH diets. The concentration of ruminal volatile fatty acids, acetic acid, and ammonia-N were higher in cows fed a 6% SH diet than in cows fed an AH diet. By comparison, the 12% SH group did not affect milk yield, milk composition, N utilization, and rumen fermentation compared with the AH and 6% SH groups. In conclusion, it appears that feeding 6% SH, replacing a portion of AH, may improve lactation performance and N utilization for lactating dairy cows.

Diet Type Impacts Production Performance of Fattening Lambs by Manipulating the Ruminal Microbiota and Metabolome.

The pelleted total mixed ration (PTMR) has a positive effect on the productivity of fattening lambs. However, whether the beneficial effects are underpinned by altering the rumen microbiota and metabolome that remain unclear. This study aimed to investigate correlations among growth performance, ruminal microbiota, and ruminal metabolome of lambs fed PTMR diet. A total of 100 crossbred (Dorper sheep × Fine-wool sheep) ram lambs at 55 days of age with similar body weight (BW) (13.2 ± 0.5 kg) were randomly allocated to 10 pens that were fed either PTMR (PTMR group) or unpelleted total mixed ration (UPTMR group) with the same dietary ingredients and nutritional contents. The average daily gain (ADG) and average daily feed intake (ADFI) were determined during the 62-day experimental period and ruminal pH, volatile fatty acid (VFA) concentrations, microbiota, and metabolome in the rumen of the lambs were examined at the end of the experiment. Compared to those of the UPTMR group, the PTMR group had greater ADFI (P = 0.002), ADG (P = 0.003), and feed efficiency (G/F) (P < 0.05). Similarly, feeding PTMR increased the concentration of total VFA (TVFA) and the molar proportion of propionate, but decreased the proportion of butyrate and acetate to propionate ratio in the rumen of lambs compared to that in lambs from the UPTMR group (P < 0.05). In addition, the PTMR group demonstrated lowered alpha-diversity of the ruminal microbiota and enhanced the relative abundance of Fibrobacter (P < 0.05), Veillonellaceae (P < 0.05), and the abundance of Rikenellaceae (P = 0.064) in the rumen compared with those in the UPTMR group. Feeding lambs with PTMR significantly upregulated the metabolic pathways involving tryptophan, histidine, cysteine and methionine, β-alanine, tyrosine metabolisms, and steroid biosynthesis. Moreover, the abundance of the microbiota strongly correlated with the altered performance, ruminal VFA, metabolites, and metabolic pathways of lambs. Taken together, feeding PTMR shaped the ruminal microbiota of lambs with decreased diversity, while improving relative abundance of some specific microbes and upregulating certain growth-related metabolic pathways, which contributed to the augmented growth performance and G/F of fattening lambs. Thus, feeding PTMR to fattening lambs for superior production performance and G/F is recommended.

Effect of Alpha-lipoic Acid on Productive Parameters and Ruminal VFA Profile in Sheep

Aims: The objective of this study was to evaluate the effect of alpha-lipoic acid (ALA) on feed over the productive parameters of sheep, as well as volatile fatty acids (VFA) in the rumen and blood glucose.&#x0D; Place and Duration of Study: The experiment was conducted at the Centro de Enseñanza, Investigación y Extensión en Producción Animal del Altiplano (CEIEPAA), located in Tequisquiapan, Querétaro-México.&#x0D; Methodology: A total of 64 sheep (Pelibuey x Dorset), two months old (32 males and 32 females with an average weight of 20.7 ± 1.3 kg) were used. Animals were housed in 16 pens, 4 animals per pen, and each pen was assigned to one of the 4 ALA inclusion treatments (0, 40, 80, 120 ppm). ALA was mixed with 50 g of ground corn to ensure its consumption; the animals of treatment 0 also received 50 g of ground corn without ALA.&#x0D; Results: Differences in weight gain were observed from day 56 in the animals supplemented with 80 ppm of ALA (P &lt; .0001) and an improvement in daily weight gain (246 g) and feed conversion (P = .05) was shown. Animals treated with 40 ppm of ALA observed lower blood glucose without affecting the productive parameters (P = .05). A lower concentration of VFA was found in the treatment 120 ppm on day 84 (334.2 ± 26.5 vs 260.0 ± 15.7; P = .05).&#x0D; Conclusion: The inclusion of 80 ppm of ALA in the diet of sheep could improve the productive parameters.

Effect of Supplementing Grass Silage-Based Diets with Concentrate Carbohydrate Sources with Different Fermentation Profiles on N Metabolism of Beef Heifers Fed to Maintenance

The synchronous supply of energy and nitrogen (N) substrates to the rumen microbes on grass silage (GS)-based diets can potentially lead to reduced levels of N excreted in the urine. The objective of this study was to evaluate the effect of supplementing GS-based diet with carbohydrate sources differing in rumen fermentation profile on N metabolism of beef heifers. Six Belgian Blue × Holstein Friesian cross beef heifers (487 ± 29 kg BW) were used in a 3 × 3 Latin Square design (n = 6). Dietary treatments were: (RB) GS supplemented with rolled barley; (MM) GS supplemented with maize meal and; (SH) GS supplemented with soya hulls offered at 40:60 forage to concentrate ratio on a dry matter (DM) basis, at maintenance feeding (40 g DM/kg BW0.75). Carbohydrate source had no effect on DM, organic matter, or N intake or total N excretion and the amount of N excreted in the urine (p &gt; 0.05). Animals offered MM excreted a higher percentage of N in the faeces and a lower percentage of N in the urine compared to animals offered RB (p &lt; 0.05). There was a time by interaction for ruminal ammonia (NH3) concentrations (p &lt; 0.01). Ruminal NH3 concentrations peaked at 2 h post-feeding for all treatments. At 3 h post-feeding, ruminal NH3 concentrations for the RB treatment remained higher compared to MM and SH treatments. Molar proportions and total ruminal volatile fatty acids were similar among dietary treatments (p &gt; 0.05). Supplementing GS-based diets with different carbohydrate sources had no impact on the total level of N excreted or the amount of N excreted in the urine. However, there was a higher percentage of N excreted in the faeces and a lower percentage of N excreted in the urine when animals were offered MM compared to those offered RB (p &lt; 0.05).

Phenotypical Variation of Ruminal Volatile Fatty Acids and pH during the Peri-Weaning Period in Holstein Calves and Factors Affecting Them.

Simple SummaryThe evolutionary course of rumen volatile fatty acids and their association with management factors during the peri-weaning period under field conditions have not been sufficiently investigated. There is a large phenotypical variability among calves in rumen parameters. There are several management factors affecting them, associated with a smooth rumen adaptation peri-weaning. The results enhance our knowledge about management practices that optimize ruminal adaptation during the weaning process.Two hundred and forty-three clinically healthy Holstein calves from eight commercial dairy farms were used to: (a) describe the evolutionary course of ruminal VFA concentration and pH during the peri-weaning period and (b) assess management factors affecting their phenotypical variation of these parameters. Management practices were recorded individually for each calf as these were not fixed within farms. Samples of ruminal fluid were collected at −7 d, 0 d, and 7 d relative to weaning. Gas chromatography was used to measure ruminal VFAs, and pH was measured on site. Linear mixed models for repeated measurements were used to assess the effects of management factors and their interactions. A large among-calves phenotypical variability was observed. Estimated marginal means showed that concentrations of acetate, butyrate, and total VFAs (but not of propionate) significantly decreased, while acetate propionate increased, from −7 d to 7 d. Age at weaning and body weight at −7 d were positively associated with total and several individual VFA concentrations. Group housing and late forage feeding pre-weaning were associated with higher VFA concentrations; the same factors, as well as step-weaning, were associated with pH values around 6. Feeding 7–8 L of milk replacer daily did not preclude a smooth transition, irrespective of weaning method.

Trace mineral source influences digestion, ruminal fermentation, and ruminal copper, zinc, and manganese distribution in steers fed a diet suitable for lactating dairy cows

High solubility of certain trace minerals (TM) in the rumen can alter nutrient digestibility and fermentation. The objectives of the present studies were to determine the effects of TM source on 1) nutrient digestibility and ruminal fermentation, 2) concentrations of soluble Cu, Zn, and Mn in the rumen following a pulse dose of TM, and 3) Cu, Zn, and Mn binding strength on ruminal digesta using dialysis against a chelating agent in steers fed a diet formulated to meet the requirements of a high producing dairy cow. Twelve Angus steers fitted with ruminal cannulae were adapted to a diet balanced with nutrient concentrations similar to a diet for a high producing lactating dairy cow for 21 d. Steers were then randomly assigned to dietary treatments consisting of 10 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either sulfate (STM), hydroxychloride (HTM) or complexed trace minerals (CTM). The experimental design did not include a negative control (no supplemental Cu, Mn, or Zn) because the basal diet did not meet the National Research Council requirement for Cu and Zn. Copper, Mn, and Zn are also generally supplemented to lactating dairy cow diets at concentrations approximating those supplied in the present study. Following a 14-d adaptation period, total fecal output was collected for 5-d. Following the fecal collection period, rumen fluid was collected for Volatile fatty acid (VFA) parameters. On the following day, the same diet was provided for 14 d, without supplemental Cu, Zn, and Mn. This period served as a wash-out period. A pulse dose of 100, 400, and 600 mg of Cu, Zn, Mn, respectively, from either STM, HTM, or CTM, was administered via ruminal cannulae to the steers on day 15. Over a 24-h period ruminal samples were obtained every 2-h. Following centrifugation, the supernatant was analyzed for Cu, Mn, and Zn. Ruminal solid digesta samples from times 0, 12, and 24 h after bolus dosing were exposed to dialysis against Tris-EDTA. Digestibility of NDF and ADF were lesser in STM vs. HTM and vs. CTM supplemented steers. Steers receiving HTM and CTM had greater total VFA concentrations than STM, and molar proportions of individual VFA were not affected by treatment. Ruminal soluble Cu and Zn concentrations were greater post dosing in STM and CTM supplemented steers at 2, 4, and 6 h for Cu and 4, 6, 8, 10 and 12 h for Zn when compared to HTM supplemented steers. The release of Cu and Zn from ruminal solid digesta following dialysis against Tris-EDTA at 12 and 24 h postdosing was greater for steers receiving HTM compared to those receiving STM or CTM. Results indicate trace mineral source impacts: 1) how tightly bound Cu and Zn are to ruminal solid digesta; 2) fiber digestion; 3) and ruminal total VFA concentrations.

Effects of replacing grain feed with rumen-protected fat on feedlot performance, ruminal parameters and blood metabolites in growing Merino lambs’ diets during the hot season

In this study, the effects of rumen-protected fat (RPF) were evaluated as an energy source for partial replacement of grain feed in the diets of Merino male lambs during the hot season. Fourteen six months old Merino male lambs weighing average of 29.59 kg were randomly allocated into two groups: control diet (CON) and diets supplemented with 30 g/kg RPF. Live weight (LW), dry matter intake (DMI) and average daily gain (ADG) were recorded, and the feed conversion ratio (FCR) was then calculated. The ruminal pH, the ruminal ammonia nitrogen concentrations (NH3-N) value, the molar proportion of volatile fatty acid (VFA), blood serum as well as hematological parameters were determined and protozoa numbers were counted. While the live weight and daily gain of the lambs were not influenced by dietary treatments, DMI was increased with RPF supplementation. The ruminal pH, VFA and ruminal NH3-N concentrations were unchanged, but the protozoa numbers decreased significantly by RPF supplementation (P&amp;lt;0.05). RPF supplementation significantly affected some serum and hematological parameters in comparison to the control group. In conclusion, RPF may be added to concentrate mixture lamb feed at the level of 30 g/kg to enhance the diet energy density without negatively changing the animal’s performance.

Intake, digestibility rumen fermentation and nitrogen balance in lambs offered alfalfa and tall fescue-mixtures harvested and ensiled after a frost

The objective of this study was to determine the effect of harvesting alfalfa (Medicago sativa L.) and tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] after frost and ensiling mixtures of these forages on silage fermentation characteristics, intake, digestibility and ruminal fermentation by ewe lambs. Forages were harvested in October of 2017, wilted, and blended as either alfalfa alone, 67% alfalfa + 33% novel endophyte-infected tall fescue, 33% alfalfa + 67% fescue, or 100% fescue. Twenty bins were lined with 2 plastic bags, packed (n = 5/trt) with the respective forages, stored for 3 months, and then assigned randomly to Dorper ewe lambs (n = 20; mean BW = 34.7 ± 6.65 kg) and offered for ad libitum consumption. Lambs were allowed 14 d of adaptation followed by 5 d of total feces and urine collection. Data were analyzed using PROC-MIXED of SAS and orthogonal polynomial contrasts were used to identify trends associated with different proportions of fescue to alfalfa. Silage total acids, lactate, and acetate concentrations increased linearly (P < 0.01), while silage ammonia decreased linearly and quadratically (P < 0.01) with increasing proportions of fescue in the silage. The proportions of lactate to total acids (g/kg total acids) increased linearly (P < 0.01) and quadratically (P = 0.02) with increasing fescue-to-alfalfa ratio. Dry matter (DM) and organic matter (OM) intake (g/kg BW), digestibility, and intake of digestible DM and OM (g/kg BW) decreased linearly (P < 0.01) as fescue proportion increased in the silages. Total ruminal volatile fatty acids (VFA), as well as concentrations of isovalerate and total branched-chain VFA decreased (P < 0.05) linearly and quadratically, butyrate and valerate decreased linearly (P < 0.01), and ruminal acetate concentrations increased (P < 0.01) linearly with increasing fescue concentration in the silage. All N utilization measurements (intake, absorption and retention) decreased with increasing fescue concentration in the silage (P < 0.01). Ensiling alfalfa with fescue that was harvested after a frost may improve forage fermentation characteristics, but may reduce intake and digestibility by lambs compared to feeding undiluted alfalfa silage.

Comparison of feeding value, ruminal fermentation and bacterial community of a diet comprised of various corn silages or combination with wheat straw in finishing beef cattle

Corn silage is an important feedstuff for cattle because of the joint provision of starch and physical effective fiber and its palatability. However, the whole plant corn silage is underproduced in some regions until today and could not be popularized in beef cattle raising. The objective of this study was to compare the feeding value, ruminal fermentation and bacterial community of a diet comprised of various corn silages or combination with wheat straw in finishing beef cattle. One hundred eighty Simmental crossbred steers were blocked (60 steers/block) on the basis of initial BW. The animals were randomly assigned to 1 of 12 identical research pens (4 pens/block; 15 steers/pen), where each of the 4 research diets was assigned to 1 pen within each block as follows: (1) the whole plant corn silage-based diet was used as the control diet (WPCS), (2) the mixed forages-based diet was formulated by replacing a portion of whole plant corn silage with wheat straw (WPCSW), (3) the corn stalklage-based diet (CS), and (4) the sweet corn stalklage-based diet (SCS). The four diets were formulated to be isonitrogenous and isoenergetic with same forage to concentrate ratio. Experimental diets were fed for 90 d; a diet digestibility trial was conducted at the end of this period. There were no effects (P = 0.596) of treatment on dry matter intake, but average daily gain was greater for steers offered the WPCS diet, intermediate with WPCSW and SCS and lowest with CS (P < 0.001). Dry matter digestibility was greater (P = 0.005) for WPCS and SCS diets than for WPCSW and CS diets. The nutrients digestibility of CS was less than observed for WPCS diet (P < 0.05). The concentrations of ruminal volatile fatty acids were highest for WPCS diet, intermediate with WPCSW diet and lowest with SCS and CS diets (P < 0.001). Diets treatment had no effect on the α-diversity of rumen bacteria in steers (P > 0.05), but only caused the change of relative abundance of Ruminococcaceae and Prevotellaceae (P = 0.036 and 0.037, respectively). In conclusion, the WPCS-based diet exhibited the highest feeding value. The SCS and WPCSW offered suitable alternatives to a WPCS based diet offered to beef cattle, with limited negative influence on growth, apparent digestibility of nutrients and ruminal bacterial microbiota. In contrast, the value of a CS-based diet was relatively poor. However, it may still be economical to substitute WPCS with relative low-quality corn silage in feedlot cattle diets.

Rumen fermentation and epithelial gene expression responses to diet ingredients designed to differ in ruminally degradable protein and fiber supplies

Although numerous studies exist relating ruminal volatile fatty acid (VFA) concentrations to diet composition and animal performance, minimal information is available describing how VFA dynamics respond to diets within the context of the whole rumen environment. The objective of this study was to characterize how protein and fiber sources affect dry matter intake, rumen pH, fluid dynamics, fermentation parameters, and epithelial gene expression. Four diet treatments (soybean meal or heat-treated soybean meal and beet pulp or timothy hay) were delivered to 10 wethers. The soybean meals served as crude protein (CP) sources while the beet pulp and timothy hay represented neutral detergent fiber (NDF) sources. Feed intake, rumen pH, fluid pool size, and fluid passage rate were unaffected by treatment. Butyrate synthesis and absorption were greater on the beet pulp treatment whereas synthesis and absorption of other VFA remained unchanged. Both CP and NDF treatment effects were associated with numerous VFA interconversions. Expression levels of rumen epithelial genes were not altered by diet treatment. These results indicate that rumen VFA dynamics are altered by changes in dietary sources of nutrients but that intake, rumen environmental parameters, and the rumen epithelium may be less responsive to such changes.

Effects of replacing magnesium oxide with calcium-magnesium carbonate with or without sodium bicarbonate on ruminal fermentation and nutrient flow in vitro

The objective of this study was to evaluate the effects of replacing magnesium oxide (MgO) with calcium-magnesium carbonate [CaMg(CO3)2] on ruminal fermentation with or without the addition of sodium bicarbonate (NaHCO3). Eight fermentors of a dual-flow continuous-culture system were distributed in a replicated (2) 4 × 4 Latin square design in a 2 × 2 factorial arrangement of treatments (magnesium sources × NaHCO3). The treatments tested were 0.21% MgO [MgO; dry matter (DM) basis; 144.8 mEq of dietary cation-anion difference (DCAD)]; 0.21% MgO + 0.50% NaHCO3 (MgO+NaHCO3; DM basis; 205.6 mEq of DCAD); 1.00% CaMg(CO3)2 [CaMg(CO3)2; DM basis; 144.8 mEq of DCAD]; and 1.00% CaMg(CO3)2 + 0.50% NaHCO3 [CaMg(CO3)2+NaHCO3; DM basis; 205.6 mEq of DCAD]. Diets were formulated to have a total of 0.28% of Mg (DM basis). The experiment consisted of 40 d, which was divided into 4 periods of 10 d each, where 7 d were used for adaptation and 3 d for sampling to determine pH, volatile fatty acids (VFA), ammonia (NH3-N), lactate, mineral solubility, N metabolism, and nutrient digestibility. The effects of Mg source [MgO vs. CaMg(CO3)2], NaHCO3 (with vs. without), and the interaction were tested with the MIXED procedure of SAS version 9.4 (SAS Institute). There was no Mg source × NaHCO3 interaction in the pH variables and mineral solubility, and Mg sources evaluated did not affect the variables related to ruminal pH and solubility of Mg. On the other hand, the inclusion of NaHCO3 increased the pH daily average, independent of Mg source, which led to a reduced time that pH was below 5.8 and decreased area under the curve. Total VFA and lactate concentration were similar among treatments regardless of NaHCO3 and Mg source; however, the molar proportion of isobutyrate and NH3-N concentration were lower in diets with CaMg(CO3)2 compared with MgO. Moreover, NaHCO3 inclusion increased NH3-N, total daily NH3-N flow, isobutyrate concentration, and acid detergent fiber digestibility. Our results showed that CaMg(CO3)2 leads to a lower NH3-N concentration and isobutyrate proportion. Therefore, because most of the tested variables were not significantly different between MgO and CaMg(CO3)2 when combined or not with NaHCO3, CaMg(CO3)2 can be a viable alternative source to replace MgO in dairy cow diets without affecting mineral solubility, ruminal pH, nutrient digestibility, total VFA, and the main ruminal VFA. Although Mg sources are known to have an alkalizing effect, NaHCO3 inclusion in diets with Mg supplementation allowed an increase in ruminal pH, as well as an increase in isobutyrate and NH3-N flow.

Growth Performance, Ruminal Volatile Fatty Acids, Health Status and Profitability in Calves Fed with Milk Supplemented with Probiotics

Growth Performance, Ruminal Volatile Fatty Acids, Health Status and Profitability in Calves Fed with Milk Supplemented with Probiotics

Effect of protein and glucogenic precursor supplementation on forage digestibility, serum metabolites, energy utilization, and rumen parameters in sheep

Supplementation of glucogenic precursors in roughage diets may increase production responses due to improved efficiencies of nutrient utilization. Therefore, the objective of this study was to determine the effect of source of supplemental glucogenic potential (GP) on forage digestibility, serum metabolites, energy utilization, and rumen parameters of growing wethers consuming a roughage diet (8.8% crude protein, 71.4% ash-free neutral detergent fiber). Crossbred wethers (49.1 ± 4.7 kg initial BW; n = 16) were utilized in a 4 × 4 replicated Latin Square design with four periods of 21 d. Supplements were designed to supplement increasing amount of GP: 1) no supplementation (CON; 0 g), 2) 40 g of calcium propionate (CAP; 30 g of GP), 3) 70 g of blood meal + 100 g of feather meal (BF; 40 g of GP), or 4) combination of CAP and BF (COMBO; 70 g of GP). Total fecal and urine collection was conducted from days 13–17 to calculate digestibility estimates and urinary losses. An acetate tolerance test was administered on day 17 to determine the effect of GP on acetate clearance. Blood samples were collected on day 19 and were analyzed for serum concentrations of glucose, urea N (SUN), non-esterified fatty acids, and amino acids. Rumen fluid was collected on day 21 to determine supplementation effects on ruminal volatile fatty acid (VFA) and ammonia concentrations. Wethers receiving BF and COMBO supplementation had greatest (P ≤ 0.01) DM and OM total tract digestibility. Supplementation did not affect (P ≥ 0.37) NDF digestibility or digestible energy. Urinary nitrogen excretion was greatest (P = 0.02) for BF and COMBO. Circulating serum essential amino acid concentration was increased (P < 0.01) in BF and COMBO compared to CAP and CON. In addition, BF and COMBO had increased (P < 0.01) SUN concentrations compared to CAP and CON. Acetate half-life was not affected (P = 0.39) by supplementation strategy. However, area under the curve (AUC) for acetate was decreased (P = 0.04) with supplementation of BF and COMBO compared to CON-fed wethers. Ruminal propionate concentration was increased (P ≤ 0.01) for wethers fed CAP and COMBO supplementation, which resulted in decreased (P ≤ 0.01) A:P ratio. Overall, these results indicate that the increased propionate supply by providing propionate salts did not result in a protein sparing impact or increased N retention.

Oxidative Stress in Dairy Cows: Insights into the Mechanistic Mode of Actions and Mitigating Strategies.

This review examines several molecular mechanisms underpinning oxidative stress in ruminants and their effects on blood and milk oxidative traits. We also investigate strategies to alleviate or repair oxidative damages by improving animal immune functions using novel feed additives. Microbial pathogenic cells, feeding management, and body condition score were some of the studied factors, inducing oxidative stress in ruminants. The predominance of Streptococcus spp. (24.22%), Acinetobacter spp. (21.37%), Romboutsia spp. (4.99%), Turicibacter spp., (2.64%), Stenotrophomonas spp. (2.33%), and Enterococcus spp. (1.86%) was found in the microbiome of mastitis cows with a decrease of d-mannose and increase of xanthine:guanine ratio when Streptococcus increased. Diversity of energy sources favoring the growth of Fusobacterium make it a keystone taxon contributing to metritis. Ruminal volatile fatty acids rose with high-concentrate diets that decreased the ruminal pH, causing a lysis of rumen microbes and release of endotoxins. Moreover, lipopolysaccharide (LPS) concentration, malondialdehyde (MDA), and superoxide dismutase (SOD) activities increased in high concentrate cows accompanied by a reduction of total antioxidant capacity (T-AOC), glutathione peroxidase (GPx), and catalase (CAT) activity. In addition, albumin and paraoxonase concentrations were inversely related to oxidative stress and contributed to the protection of low-density and high-density lipoproteins against lipid peroxidation, protein carbonyl, and lactoperoxidase. High concentrate diets increased the expression of MAPK pro-inflammatory genes and decreased the expression of antioxidant genes and proteins in mammary epithelial tissues. The expression levels of NrF2, NQO1, MT1E, UGT1A1, MGST3, and MT1A were downregulated, whereas NF-kB was upregulated with a high-grain or high concentrate diet. Amino-acids, vitamins, trace elements, and plant extracts have shown promising results through enhancing immune functions and repairing damaged cells exposed to oxidative stress. Further studies comparing the long-term effect of synthetic feed additives and natural plant additives on animal health and physiology remain to be investigated.