Effects of replacing soybean meal with canola meal differing in rumen-undegradable protein content on ruminal fermentation and gas production kinetics using 2 in vitro systems

Nutrient digestibility, characteristics of rumen fermentation, and microbial protein synthesis from Pesisir cattle diet containing non-fiber carbohydrate to rumen degradable protein ratio and sulfur supplement

Background and Aim

To achieve optimal feed efficiency in ruminants, especially Pesisir cattle, it is necessary to maintain a harmonious equilibrium between energy and protein levels within the rumen. Sulfur supplementation can potentially escalate the energy-protein balance in the rumen. The aim of this study was to explore the formulation of ruminant diets by synchronizing rumen degradable protein (RDP) and non-fiber carbohydrate (NFC) while adding sulfur minerals at different levels. Nutrient digestibility, NH3 concentration, volatile fatty acids (VFA) production, microbial protein synthesis (MPS), and methane gas production were assessed.

Materials and Methods

We employed a randomized block design with a 2 × 2 × 3 factorial arrangement and examined diverse incubation periods of 6, 24, and 48 h. Treatment consisted of RDP (60% and 65%), NFC (35% and 40%), and sulfur (0%, 0.15%, and 0.3%) levels. In this study, the Tilley and Terry in vitro technique, which used Pesisir cattle's rumen fluid, was employed to assess the digestibility of dry matter, organic matter, acid detergent fiber, neutral detergent fiber, and RDP-Rumen undegradable protein. In addition, it measures various rumen fluid attributes, including pH, NH3, VFA, MPS, and methane gas production.

Results

Treatment with a coordinated combination of 65% RDP and 40% NFC combined with 0.15% sulfur supplement yielded significantly improved digestibility and notably reduced methane gas production (p < 0.05).

Conclusion

The enhancement in digestibility and reduction in methane gas emissions can be attributed to the interaction of RDP, NFC, and sulfur. Feed digestibility was increased in the 65% RDP treatment with 40% NFC and 0.15% sulfur, along with a decrease in methane gas production.

Effects of monensin and cashew nut-shell extract on bacterial community composition in a dual-flow continuous culture system

The objective of this study was to evaluate the effects of including monensin and two doses of CNSE in a high producing dairy cow diet on ruminal bacterial communities. A dual-flow continuous culture system was used in a replicated 4 × 4 Latin Square design. A basal diet was formulated to meet the requirements of a cow producing 45 kg of milk per d (17% crude protein and 27% starch). There were four experimental treatments: the basal diet without any feed additive (CON), 2.5 μM monensin (MON), 100 ppm CNSE granule (CNSE100), and 200 ppm CNSE granule (CNSE200). Samples were collected from the fluid and solid effluents at 3, 6, and 9 h after feeding; a composite of all time points was made for each fermenter within their respective fractions. Bacterial community composition was analyzed by sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform. Treatment responses for bacterial community structure were analyzed with the PERMANOVA test run with the R Vegan package. Treatment responses for correlations were analyzed with the CORR procedure of SAS. Orthogonal contrasts were used to test the effects of (1) ADD (CON vs. MON, CNSE100, and CNSE200); (2) MCN (MON vs. CNSE100 and CNSE200); and (3) DOSE (CNSE100 vs. CNSE200). Significance was declared at P ≤ 0.05. We observed that the relative abundance of Sharpea (P < 0.01), Mailhella (P = 0.05), Ruminococcus (P = 0.03), Eubacterium (P = 0.01), and Coprococcus (P < 0.01) from the liquid fraction and the relative abundance of Ruminococcus (P = 0.03) and Catonella (P = 0.02) from the solid fraction decreased, while the relative abundance of Syntrophococcus (P = 0.02) increased in response to MON when compared to CNSE treatments. Our results demonstrate that CNSE and monensin have similar effects on the major ruminal bacterial genera, while some differences were observed in some minor genera. Overall, the tested additives would affect the ruminal fermentation in a similar pattern.

Effects of cashew nutshell extract and monensin on microbial fermentation in a dual-flow continuous culture

The objective of this study was to compare cashew nutshell extract (CNSE) to monensin and evaluate changes in in vitro mixed ruminal microorganism fermentation, nutrient digestibility, and microbial nitrogen outflow. Treatments were randomly assigned to 8 fermenters in a replicated 4 × 4 Latin square design with 4 experimental periods of 10 d (7 d for diet adaptation and 3 d for sample collection). Basal diets contained 43.5:56.5 forage: concentrate ratio and each fermenter was fed 106 g of DM/d divided equally between 2 feeding times. Treatments were control (CON, basal diet without additives), 2.5 μM monensin (MON), 0.1 mg CNSE granule/g DM (CNSE100), and 0.2 mg CNSE granule/g DM (CNSE200). On d 8 to10, samples were collected for pH, lactate, NH3-N, volatile fatty acids (VFA), mixed protozoa counts, organic matter (OM), and neutral detergent fiber (NDF) digestibility. Data were analyzed with the GLIMMIX procedure of SAS. Orthogonal contrasts were used to test the effects of (1) ADD (CON vs. MON, CNSE100, and CNSE200); (2) MCN (MON vs. CNSE100 and CNSE200); and (3) DOSE (CNSE100 vs. CNSE200). We observed that butyrate concentration in all treatments was lower compared with CON and the concentration for MON was lower compared with CNSE treatments. Protozoal population in all treatments was lower compared with CON. No effects were observed for pH, lactate, NH3-N, total VFA, OM, or N utilization. Within the 24-h pool, protozoal generation time, tended to be lower, while NDF digestibility tended to be greater in response to all additives. Furthermore, the microbial N flow, and the efficiency of N use tended to be lower for the monensin treatment compared with CNSE treatments. Overall, our results showed that both monensin and CNSE decreased butyrate synthesis and protozoal populations, while not affecting OM digestibility and tended to increase NDF digestibility; however, such effects are greater with monensin than CNSE nutshell.

Evaluation of in vitro digestibility of Aspergillus oryzae fungal biomass grown on organic residue derived-VFAs as a promising ruminant feed supplement

BACKGROUND

As demand for high quality animal feed continues to raise, it becomes increasingly important to minimize the environmental impact of feed production. An appealing sustainable approach to provide feed fractions is to use organic residues from agro-food industry. In this regard, volatile fatty acids (VFAs) such as acetic, propionic and butyric acids, derived from bioconversion of organic residues can be used as precursors for production of microbial protein with ruminant feed inclusion potential. This study aims to investigate the in vitro digestibility of the Aspergillus oryzae edible fungal biomass cultivated on VFAs-derived from anaerobic digestion of residues. The produced fungal protein biomass, along with hay clover silage and rapeseed meal were subjected to various in vitro assays using two-stage Tilley and Terry (TT), gas, and bag methods to evaluate and compare its digestibility for application in ruminant feed.

RESULTS

The produced fungal biomass contained a higher crude protein (CP) (41%-49%) and rather similar neutral detergent fiber (NDF) (41%-56%) compared to rapeseed meal. The rumen in vitro dry matter digestibility (IVDMD) of the fungal biomass in the TT method ranged from 82% to 88% (statistically similar to that of the gas method (72% to 85%)). The IVDMD of fungal biomass were up to 26% and 40% greater than that of hay clover silage and rapeseed meal, respectively. The type of substrate and bag method had pronounced effect on the fermentation products (ammonium-N (NH4+-N), total gas and VFAs). Fungal biomass digestion resulted in the highest release of NH4+-N (340-540 mg/L) and the ratio of acetate to propionate ratio (3.5) among subjected substrates.

CONCLUSION

The results indicate that gas method can be used as a reliable predictor for IVDMD as well as fermentation products. Furthermore, the high IVDMD and fermentation product observed for Aspergillus oryzae fungal biomass digestion, suggest that the supplementation of fungal biomass will contribute to improving the rumen digestion by providing necessary nitrogen and energy to the ruminant and microbiota.

Production effects of extruded soybean meal replacing canola meal in the diet of lactating dairy cows

This study investigated the effects of extruded soybean meal (ESBM) in comparison with canola meal (CM) fed on an equivalent crude protein (CP) basis on lactational performance and ruminal fermentation of dairy cows. Following a 2-wk covariate period, 48 Holstein cows averaging (±SD): 146 ± 46 d in milk (DIM) and 43 ± 7 kg/d milk yield (MY) were assigned 1 of 2 treatment diets in a randomized complete block design experiment, which included a 2-wk period for dietary treatment adaptation before experimental data were collected. Following the adaptation period, samples and experimental data were collected for a total of 7 wk. Cows were blocked based on parity, DIM, and MY. Treatment diets contained 15.8% CM (containing 41.2% CP) or 13.2% ESBM (with 48.7% CP) of total mixed ration dry matter (DM), with similar inclusion of other feed ingredients. The CM diet was supplemented with canola oil, whereas the ESBM diet was supplemented with soybean hulls to achieve similar ether extract and neutral detergent fiber contents between the diets. Urea and rumen-protected Met and Lys were added to both diets to meet or exceed cow recommendations. Whole-ruminal digesta samples were collected from 10 (5 per treatment) ruminally cannulated cows. Eight cannulated cows were removed during the last week of the experiment to participate in another study. Treatment did not affect DM intake and MY or energy-corrected MY of the cows. Energy-corrected MY, apart from experimental wk 5, was similar between treatments. Apart from experimental wk 3 and 7, milk fat concentration and yield were greater for cows fed ESBM compared with CM. In multiparous cows only, milk true protein yield was greater for cows fed CM compared with ESBM. Ruminal concentration of total volatile fatty acids and the molar proportion of acetate were greater for ESBM, and propionate and valerate were greater in cows fed CM. Acetate to propionate ratio was greater for cows fed ESBM versus CM diet. Compared with the CM diet, the ESBM diet increased plasma concentrations of Ile, Leu, and Phe but not the sum of essential AA. Apparent total-tract digestibility of acid detergent fiber was greater in cows fed ESBM relative to CM. In this experiment, CM and ESBM included on an equal CP basis in the diet of dairy cows, resulted in similar DM intake, MY, and feed efficiency.

Production of 17 strains of edible mushroom grown on corn stover and its effect on the chemical composition and ruminal in vitro digestibility of the residual substrate

The objective of this study was to evaluate the production (P) (g of fresh mushrooms /bag) and biological efficiency (BE) (g of fresh mushrooms per 100 g of dry substrate) of 17 fungal strains, namely Pleurotus ostreatus Po-IAP, Po-P38, Po-P14, Po-IE202, Po-Sfco, Po-JP, Po-Psma, and Po-POS, Pleurotus djamour Pd-PRO and Pd-UTMR, Pleurotus eryngii Pe-MB and Pe-PQ, Lentinula edodes L15, L9, L5, and LC, and Hericium erinaceus Heri, produced in corn stover (CS) and to assess the content of crude protein (CP), lignin (L), cellulose, hemicellulose, acid detergent fiber (ADF), and neutral detergent fiber (NDF) and in vitro digestibility of dry matter (IVDMD) of the residual substrate of CS, the so called spent mushroom substrate (SMS), in comparison to the non-inoculated substrate (C). The variables were analyzed as a completely randomized block design using R 4.0.3 software. Means were compared using Tukey's procedure. The Pleurotus spp. strains, compared to Lentinula spp. and Hericium spp., presented better BE and P. In comparison to C, the SMS increased the CP content (p < 0.05) from 10.8% (Po-JP) to 70.3% (LC), while NDF decreased (p < 0.05) from 11.5% (Pd-Pro) to 33.5% (L15) and IVDMD increased (p < 0.05) from 16.2% (Heri) to 47.7% (Pd-UTMR). In conclusion, of the 17 strains evaluated, the 3 strains of Lentinula edodes (L5, L15, and L9), one strain of Pleurotus djamour (Pd-UTMR), and one strain of Pleurotus ostreatus (Po-IAP) generated a SMS that, due to its nutritional improvement and increase in IVDMD, could be used as feed for ruminants. Our results also showed that corn stover is a suitable substrate to produce Pleurotus spp. fruiting bodies, with strain Po-IAP as the best yielding.

Effect of replacing cottonseed meal with canola meal on growth performance, blood metabolites, thyroid function, and ruminal parameters of growing lambs

The objective was to clarify the impact of replacing cottonseed meal with canola meal (CM) on growth performance, blood metabolites, thyroxin function, and ruminal parameters of growing lambs. Twenty-four growing Barki male lambs (4-5 months of age) were assigned randomly into four equal groups (6 lambs each). Four dietary treatments were the control group with 0% CM (CON) and three experimental groups where CM replaced 25% (CN₁), 50% (CN₂), and 75% (CN₃) of cottonseed meal. There were no dietary effects (P > 0.05) on the lambs' feed intake, average daily gain, and feed conversion ratio of the lambs. The dietary CM linearly decreased the concentrations of serum total proteins (P = 0.003), albumin (P = 0.010), globulin (P = 0.011), AST (P = 0.041), and urea (P = 0.001) in growing lambs. The levels of ALT and creatinine, however, were not significantly affected by dietary treatments (P > 0.05). Furthermore, serum triiodothyronine, thyroxine, and electrolyte concentrations were similar (P > 0.05) in different dietary groups. Dietary treatments significantly affected the values of ruminal pH and ammonia at 0 h (P = 0.003 and 0.048, respectively) and 3 h (P = 0.033 and P = 0.006, respectively) postfeeding. The CN₃ group showed significantly higher concentrations of ruminal ammonia at 0 and 3 h postfeeding. Furthermore, dietary CM (CN₃) significantly reduced the ruminal pH values at 0 and 3 h postfeeding. Meanwhile, dietary treatments did not affect the concentration of total VFAs in the ruminal fluid. In conclusion, CM can replace the cottonseed meal (up to 75%) in lamb diets without compromising their growth performance, thyroid function, and ruminal fermentation parameters.

Effects of exogenous amylolytic or fibrolytic enzymes inclusion on in vitro fermentation of lactating dairy cow diets in a dual-flow continuous-culture system

The objective of this study was to determine the effects of including exogenous amylolytic or fibrolytic enzymes in a diet for high-producing dairy cows on in vitro ruminal fermentation. Eight dual-flow continuous-culture fermentors were used in a replicated 4 × 4 Latin square. The treatments were control (CON), a xylanase and glucanase mixture (T1), an α-amylase mixture (T2), or a xylanase, glucanase, and α-amylase mixture (T3). Treatments were included at a rate of 0.008% of diet dry matter (DM) for T1 and T2 and at 0.02% for T3. All treatments replaced the equivalent amount of soybean meal in the diet compared with CON. All diets were balanced to have the same nutrient composition [30.2% neutral detergent fiber (NDF), 16.1% crude protein (CP), and 30% starch; DM basis], and fermentors were fed 106 g/d divided into 2 feedings. At each feeding, T2 was pipetted into the respective fermentor and an equivalent amount of deionized water was added to each fermentor to eliminate potential variation. Experimental periods were 10 d (7 d for adaptation and 3 d for sample collection). Composite samples of daily effluent were collected and analyzed for volatile fatty acids (VFA), NH₃-N, and lactate concentrations, degradability of DM, organic matter, NDF, CP, and starch, and flow and metabolism of N. Samples of fermentor contents were collected from each fermentor at 0, 1, 2, 4, 6, and 8 h after feeding to determine kinetics of pH, NH₃-N, lactate, and VFA concentrations over time. All data were analyzed using PROC GLIMMIX of SAS (SAS Institute Inc.), and the repeated variable of time was included for kinetics measurements. Treatment did not affect mean pH, degradability, N flow and metabolism, or the concentrations of VFA, NH₃-N, or lactate in the effluent samples. Treatment did not affect pH, acetate:propionate ratio, or the concentrations of lactate, NH₃-N, total VFA, acetate, propionate, butyrate, isobutyrate, valerate, or caproate. However, the concentration of total VFA tended to change at each time point depending upon the treatment, and T2 tended to have a greater proportion of 2-methylbutyrate and isovalerate than CON, T1, or T3. As 2-methylbutyrate and isovalerate are branched-chain VFA that are synthesized from branched-chain amino acids, T2 may have an increased fermentation of branched-chain amino acids or decreased uptake by fibrolytic microorganisms. Although we did not observe changes in N metabolism due to the enzymes, there could be changes in microbial populations that utilize branched-chain VFA. Overall, the tested enzymes did not improve in vitro ruminal fermentation in the diet of high-producing dairy cows.

Megasphaera elsdenii and Saccharomyces Cerevisiae as direct fed microbials during an in vitro acute ruminal acidosis challenge

This study aimed to evaluate the effects of Saccharomyces cerevisiae and Megasphaera elsdenii as direct fed microbials (DFM) in beef cattle finishing diets to alleviate acute ruminal lactic acidosis in vitro. A dual-flow continuous culture system was used. Treatments were a Control, no DFM; YM1, S. cerevisiae and M. elsdenii strain 1; YM2, S. cerevisiae and M. elsdenii strain 2; and YMM, S. cerevisiae and half of the doses of M. elsdenii strain 1 and strain 2. Each DFM dose had a concentration of 1 × 10⁸ CFU/mL. Four experimental periods lasted 11 days each. For the non-acidotic days (day 1–8), diet contained 50:50 forage to concentrate ratio. For the challenge days (day 9–11), diet contained 10:90 forage to concentrate ratio. Acute ruminal acidosis was successfully established. No differences in pH, d-, l-, or total lactate were observed among treatments. Propionic acid increased in treatments containing DFM. For N metabolism, the YMM treatment decreased protein degradation and microbial protein synthesis. No treatment effects were observed on NH₃–N concentration; however, efficiency of N utilization by ruminal bacteria was greater than 80% during the challenge period and NH₃–N concentration was reduced to approximately 2 mg/dL as the challenge progressed.

Use of Camelina sativa and By-Products in Diets for Dairy Cows: A Review

Camelina sativa, belonging to the Brassicaceae family, has been grown since 4000 B.C. as an oilseed crop that is more drought- and cold-resistant. Increased demand for its oil, meal, and other derivatives has increased researchers’ interest in this crop. Its anti-nutritional factors can be reduced by solvent, enzyme and heat treatments, and genetic engineering. Inclusion of camelina by-products increases branched-chain volatile fatty acids, decreases neutral detergent fiber digestibility, has no effect on acid detergent fiber digestibility, and lowers acetate levels in dairy cows. Feeding camelina meal reduces ruminal methane, an environmental benefit of using camelina by-products in ruminant diets. The addition of camelina to dairy cow diets decreases ruminal cellulolytic bacteria and bio-hydrogenation. This reduced bio-hydrogenation results in an increase in desirable fatty acids and a decrease in saturated fatty acids in milk obtained from cows fed diets with camelina seeds or its by-products. Studies suggest that by-products of C. sativa can be used safely in dairy cows at appropriate inclusion levels. However, suppression in fat milk percentage and an increase in trans fatty acid isomers should be considered when increasing the inclusion rate of camelina by-products, due to health concerns.

Supplementation of Oilseeds to an Herbage Diet High in Condensed Tannins Affects Methane Production with Minimal Impact on Ruminal Fermentation in Continuous Culture

Condensed tannins (CT) have been observed to reduce enteric CH4 production when added to ruminant diets. However, high concentrations of CT in forages such as sericea lespedeza (SL; Lespedeza cuneata (Dum. Cours.) G. Don) may depress nutrient digestibility. Oilseed crops, high in lipid concentration, also reduce enteric CH4 via toxicity to methanogenic bacteria with less depression of nutrient digestibility. However, it is unclear whether combining these two feeds would result in even greater decreases in CH4 without impairing ruminal fermentation. This study used an in vitro continuous culture fermentor system to determine if supplementation of ground oilseeds would further reduce enteric CH4 production while improving nutrient digestibility of high-CT forages. The experimental design was a 4 × 4 Latin square, with four diets containing (dry matter basis) 45% orchardgrass (OCH; Dactylis glomerata L.), 45% sericea lespedeza (SL; Lespedeza cuneata (Dum. Cours.) G. Don), and 10% oilseed supplements, using canola (CAN; Brassica napus L.), soybean (SOY; Glycine max L.), sunflower (SUN; Helianthus annuus L.), or a mix of all three species (MIX; in equal proportions). Fermentors were fed 82 g of dry matter/d in four equal feedings over four 10 d periods. Methane was recorded every 10 min, and effluent samples were analyzed for pH, volatile fatty acids, dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber to determine apparent and true nutrient digestibilities. The CAN, SUN, and MIX diets had greater concentrations of crude fat (7–8 g/kg) than the SOY diet (5.7 g/kg), which contributed to the greater reduction in enteric CH4 production in those diets (13–27 mg/d) compared to the SOY diet (84 mg/d). Apparent and true nutrient digestibilities were not affected by the addition of ground oilseeds. While N intake increased concomitant with crude protein increases in the diets, there were no additional effects on N flows. While supplementing a high-CT diet with any of the three oilseeds (canola, soybean, sunflower, or a mixture of the three oilseeds) reduced total CH4 emission without depressing nutrient digestibility, canola and mixes containing canola were most effective. Further research is needed in vivo to evaluate whether these results translate to greater feed efficiency and animal production.

Dietary Administration of L-Carnitine During the Fattening Period of Early Feed Restricted Lambs Modifies Ruminal Fermentation but Does Not Improve Feed Efficiency

Early feed restriction of lambs may program animals to achieve reduced feed efficiency traits as a consequence of permanent mitochondrial dysfunction. The hypothesis at the background of the present study is that dietary administration of L-Carnitine (a compound that promotes the activation and transportation of fatty acids into the mitochondria) during the fattening period of early feed restricted lambs can: (a) improve the biochemical profile of early feed restricted lambs, (b) improve feed efficiency, (c) modulate the ruminal and intestinal microbiota, and (d) induce changes in the gastrointestinal mucosa, including the immune status. Twenty-two newborn male Merino lambs were raised under natural conditions but separated from the dams for 9 h daily to allow feed restriction during the suckling period. At weaning, lambs were assigned to a control group being fed ad libitum a complete pelleted diet during the fattening phase (CTRL, n = 11), whereas the second group (CARN, n = 11) received the same diet supplemented with 3 g of L-Carnitine/kg diet. The results revealed that even though L-Carnitine was absorbed, feed efficiency was not modified by dietary L-Carnitine during the fattening period (residual feed intake, p &gt; 0.05), whereas ruminal fermentation was improved [total short-chain fatty acids (SCFAs), 113 vs. 154 mmol/l; p = 0.036]. Moreover, a trend toward increased concentration of butyrate in the ileal content (0.568 vs. 1.194 mmol/100 ml SCFA; p = 0.074) was observed. Other effects, such as reduced heart weight, lower levels of markers related to muscle metabolism or damage, improved renal function, and increased ureagenesis, were detected in the CARN group. Limited changes in the microbiota were also detected. These findings suggest that L-Carnitine may improve ruminal fermentation parameters and maintain both the balance of gut microbiota and the health of the animals. However, the improved ruminal fermentation and the consequent greater accumulation of intramuscular fat might have hidden the effects caused by the ability of dietary L-Carnitine to increase fatty acid oxidation at the mitochondrial level. This would explain the lack of effects of L-Carnitine supplementation on feed efficiency and points toward the need of testing lower doses, probably in the context of animals being fed in excess non-protein nitrogen.

Effects of different protein sources on nutrient disappearance, rumen fermentation parameters and microbiota in dual-flow continuous culture system

Scarce high-quality protein feed resources has limited the development of animal husbandry. In this study, we used a dual-flow continuous culture system to evaluate effects of difference dietary protein sources including soybean meal (SBM), cottonseed meal (CSM), and rapeseed meal (RSM), on nutrient disappearance, rumen fermentation, and microbiota of XiongDong black goats. Dietary proteins of either CSM, RSM or SBM had no effect on nutrient disappearance (P > 0.05). CSM or RSM significantly reduced (P < 0.01) the pH and enhanced (P < 0.01) the ammonia nitrogen (NH₃-N) concentration in fermentation liquid compared to SBM. The short-chain fatty acids (SCFAs) contents were greater (P = 0.05) and acetate was lower (P < 0.01) in SBM than those in RSM and CSM, whereas propionate was greater (P < 0.01) in RSM than that in SBM, consequently reducing the acetate to propionate ratio (A/P) in RSM. Bacteroidetes, Firmicutes, and Proteobacteria were detected as the dominant phyla, and the relative abundances of Spirochaetae (P < 0.01) and Chlorobi (P < 0.05) declined in the CSM and RSM groups as compared to those in the SBM group. At the genus level, Prevotella_1 was the dominant genus; as compared to SBM, its relative abundance was greater (P < 0.01) in CSM and RSM. The abundances of Prevotellaceae_Ga6A1 and Christensenellaceae_R7 were lower (P < 0.05) in CSM, whereas Eubacterium_oxidoreducens_group, and Treponema_2 were lower (P < 0.01) in both CSM and RSM, and other genera were not different (P > 0.10). Although the bacterial community changed with different dietary protein sources, the disappearances of nutrients were not affected, suggesting that CSM and RSM could be used by rumen bacteria, as in case with SBM, and are suitable protein sources for ruminant diets.

Synchronization of rumen degradable protein with non-fiber carbohydrate on microbial protein synthesis and dairy ration digestibility

Background and Aim: Dairy ration formulations should consider the synchronization of the rumen degradable protein (RDP) to rumen undegradable protein (RUP) ratio (RDPR) with non-fiber carbohydrate (NFC) to achieve optimum microbial protein synthesis (MPS), reduce feed costs, and reduce N excretion to the environment. This study aimed to investigate the effect of RDPR and NFC synchronization on in vitro digestibility, fermentability, and MPS. Materials and Methods: The experiment used a 3×3 factorial randomized block design with four replications. The first factor was RDPR (RDPR1=50:50; RDPR2=55:45; RDPR3=60:40) and the second factor was NFC levels (NFC1=30%, NFC2=35%, NFC3=40%). The experimental diets were evaluated using a two-stage in vitro method. The examined parameters included rumen pH, NH3 concentration, total volatile fatty acid (VFA) concentration, the molar proportion of VFAs, rumen microbes (protozoa and total bacteria population), and MPS. Data were analyzed using ANOVA, followed by the Duncan test. Results: The results show that neither RDPR nor NFC affected rumen pH, NH3, total VFA, and the rumen microbe population. The interaction between RDPR and NFC affected the molar proportion of acetate, iso-butyrate, and n-valerate. The combination of RDPR1 and NFC1 produced a lower molar proportion of acetate (49.73%) than the other treatment combinations (>54%). The acetate to propionate ratio was influenced by the NFC levels, in which NFC2 and NFC3 produced the highest ratio (p<0.05). MPS was affected by RDPR and NFC, but not by their interaction. Treatments NFC2 and RDPR3 produced the highest MPS. NFC affected the dry matter and organic matter digestibility (DMD and OMD), with treatment NFC3 resulting in the highest DMD and OMD. Conclusion: The combination of a 60:40 RDPR with 35% NFC resulted in the best synchronization of protein and energy available for MPS and digestion activity in the rumen.

Effects of lactic acid-producing bacteria as direct-fed microbials on the ruminal microbiome

The objective of this study was to evaluate ruminal microbiome changes associated with feeding Lactobacillus plantarum GB-LP1 as direct-fed microbials (DFM) in high-producing dairy cow diets. A dual-flow continuous culture system was used in a replicated 4 × 4 Latin square design. A basal diet was formulated to meet the requirements of a cow producing 45 kg of milk per day (16% crude protein and 28% starch). There were 4 experimental treatments: the basal diet without any DFM (CTRL); a mixture of Lactobacillus acidophilus, 1 × 10⁹ cfu/g, and Propionibacterium freudenreichii, 2 × 10⁹ cfu/g [MLP = 0.01% of diet dry matter (DM)]; and 2 different levels of L. plantarum, 1.35 × 10⁹ cfu/g (L1 = 0.05% and L2 = 0.10% of diet DM). Bacterial samples were collected from the fluid and particulate effluents before feeding and at 2, 4, 6, and 8 h after feeding; a composite of all time points was made for each fermentor within their respective fractionations. Bacterial community composition was analyzed through sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform. Sequenced data were analyzed on DADA2, and statistical analyses were performed in R (RStudio 3.0.1, https://www.r-project.org/) and SAS 9.4 (SAS Institute Inc.); orthogonal contrasts were used to compare treatments. Different than in other fermentation scenarios (e.g., silage or beef cattle high-grain diets), treatments did not affect pH or lactic acid concentration. Effects were mainly from overall DFM inclusion, and they were mostly observed in the fluid phase. The relative abundance of the phylum Firmicutes, family Lachnospiraceae, and 6 genera decreased with DFM inclusion, with emphasis on Butyrivibrio_2, Saccharofermentans, and Ruminococcus_1 that are fibrolytic and may display peptidase activity during fermentation. Lachnospiraceae_AC2044_group and Lachnospiraceae_XPB1014_group also decreased in the fluid phase, and their relative abundances were positively correlated with NH₃-N daily outflow from the fermentors. Specific effects of MLP and L. plantarum were mostly in specific bacteria associated with proteolytic and fibrolytic functions in the rumen. These findings help to explain why, in the previous results from this study, DFM inclusion decreased NH₃-N concentration without altering pH and lactic acid concentration.

Diet supplementation with canola meal improves milk production, reduces enteric methane emissions, and shifts nitrogen excretion from urine to feces in dairy cows

The objective of this study was to examine the effect of isonitrogenous substitution of solvent-extracted soybean meal (SBM) with solvent-extracted canola meal (CM) on enteric CH₄ production, ruminal fermentation characteristics (including protozoa), digestion (in situ and apparent total-tract digestibility), N excretion, and milk production of dairy cows. For this purpose, 16 lactating Holstein cows, of which 12 were ruminally cannulated, were used in a replicated 4 × 4 Latin square (35-d periods; 14-d adaptation). The cows averaged (mean ± SD) 116 ± 23 d in milk, 692 ± 60 kg of body weight, and 47.5 ± 4.9 kg/d of milk production. The experimental treatments were control diet (no CM; 0%CM) and diets supplemented [dry matter (DM) basis] with 7.9% CM (8%CM), 15.8% CM (16%CM), or 23.7% CM (24%CM) on a DM basis. The forage:concentrate ratio was 52:48 (DM basis) and was similar among the experimental diets. Canola meal was included in the diet at the expense of SBM and soybean hulls, whereas the percentages of the other diet ingredients were the same. Intake of DM increased linearly, whereas apparent total-tract digestibility of DM, crude protein, neutral detergent fiber, and gross energy (GE) declined linearly as CM inclusion in the diet increased. Total volatile fatty acids concentration and butyrate molar proportion decreased linearly, whereas molar proportion of propionate increased linearly, and that of acetate was unaffected by CM inclusion in the diet. Ruminal ammonia concentration was not affected by inclusion of CM in the diet. Energy-corrected milk (ECM) yield increased linearly (up to 2.2 kg/d) with increasing CM percentage in the diet, whereas milk production efficiency averaged 1.63 kg of ECM/kg of DM intake and was unaffected by CM inclusion in the diet. Daily CH₄ production decreased linearly with increasing CM percentage in the diet (489, 475, 463, and 461 g/d for 0%CM, 8%CM, 16%CM and 24%CM diets, respectively). As a consequence, CH₄ emission intensity (g of CH₄/kg of ECM) also declined linearly by up to 10% as the amount of CM increased in the diet. Methane production also decreased linearly when expressed relative to GE intake (5.7, 5.2, 5.1, and 4.9% for 0%CM, 8%CM, 16%CM and 24%CM diet, respectively). Quantity of manure N excretion was not affected by replacing SBM with CM; however, N excretion shifted from urine to feces as dietary percentage of CM increased, suggesting reduced potential for N volatilization. Results from this study show that replacing SBM with CM as a protein source in dairy cow diets reduced enteric CH₄ emissions (g/d, % of GE intake, and adjusted for milk production) and increased milk production. The study indicates that CM can successfully, partially or fully, replace SBM in lactating dairy cow diets, with positive effects on animal productivity and the environment (i.e., less enteric CH₄ emission and urinary N excreted). We conclude that compared with SBM, inclusion of CM meal in dairy cow diets can play a key role in reducing the environmental footprint of milk production.

Effects of canola meal inclusion rate in starter mixtures for Holstein heifer calves on dry matter intake, average daily gain, ruminal fermentation, plasma metabolites, and total-tract digestibility

The objective of this study was to determine the effects of the canola meal (CM) inclusion rate in pelleted starter mixtures for Holstein heifer calves on dry matter intake, average daily gain, ruminal fermentation, plasma metabolites, and total-tract digestibility. Fifty Holstein heifer calves were blocked by birth date and body weight and, within block, randomly assigned to 1 of 5 pelleted starter treatments with 0, 15, 30, 45, or 60% of the crude protein supplied by CM instead of soybean meal (SBM). Pellets were formulated to be similar in crude protein (24.3%), starch (26.6%), and neutral detergent fiber (17.8%) and were provided to calves starting on d 8 of age, with starter intake measured daily. From 8.0 ± 0.0 (mean ± standard deviation) d of age through d 35.3 ± 2.4, calves were fed milk replacer at 15% of body weight, offered in 3 equal feedings at 0600, 1500, and 2100 h. After that, a gradual 21-d step-down weaning process was imposed, where no further milk replacer was provided starting on d 57.0 ± 0.0. Data for milk replacer and starter intake were calculated to determine weekly averages. On d 62.2 ± 0.8 of age, blood was collected every 4 h and analyzed for glucose, β-hydroxybutyrate, insulin, and urea concentrations. From d 66.2 ± 0.8 of age and extending for 3 d, fecal samples were collected every 12 h with a 3-h daily offset, to estimate fecal nutrient output and to determine apparent total-tract digestibility. Additionally, ruminal fluid (d 70.2 ± 0.8 of age) was sampled at 1300 h through an esophageal tube connected to a vacuum pump. The pH of ruminal fluid was measured, and ruminal fluid was analyzed to determine short-chain fatty acid and ammonia concentrations. Data were analyzed with fixed effect of treatment and random effect of block. Polynomial contrasts were calculated to assess linear, quadratic, and cubic effects with repeated measures statement for variables analyzed over time. Starter intake, average daily gain, body weight, and feed efficiency did not differ among treatments. Crude protein and ether extract digestibility were affected in a cubic manner, where CP was greatest for CM0, CM30, and CM45, and ether extract digestibility was least for CM15 and CM60. The molar proportion of acetate responded cubically, but the proportions of propionate and butyrate did not differ among treatments. Ruminal ammonia and plasma urea concentrations were not affected by CM inclusion rate. In conclusion, CM can replace up to 60% of the CP provided from SBM without affecting starter intake and growth of calves.

Effects of rumen-degradable-to-undegradable protein ratio in ruminant diet on in vitro digestibility, rumen fermentation, and microbial protein synthesis

BACKGROUND AND AIM

Feeding ruminants must notice the degradability of feed, especially protein. Microbial rumen requires ammonia from rumen degradable protein (RDP) beside that ruminant require bypass protein or rumen undegradable protein (RUP) and microbial crude protein. The aim of the study was to discover the best RDP:RUP ratio in beef cattle diets commonly used by Indonesian farmers using an in vitro methodology.

MATERIALS AND METHODS

Samples of Pennisetum purpureum, Leucaena leucocephala, Indigofera zollingeriana, cassava, maize, palm kernel cake, rice bran, and tofu waste were formulated into dietary treatments (dry matter [DM] basis). All experiments were carried out using a 3×3×2 factorial, randomized block design with three replications. Treatments consisted of three protein levels (12%, 14%, and 16%), two energy levels (65% and 70%), and three RDP:RUP ratio levels (55:45, 60:40, and 65:35). The experimental diets were incubated in vitro using buffered rumen fluid for 48 h at 39°C. After incubation, the supernatants were analyzed to determine pH, ammonia concentration, total volatile fatty acid (VFA), and microbial protein synthesis. The residues were analyzed to determine DM, organic matter, protein, and RUP digestibility.

RESULTS

Increased protein, energy, and RDP levels increased digestibility, ammonia concentrations, total VFAs, and microbial protein synthesis (p<0.05), while rations with 16% protein lowered these parameters (p<0.05).

CONCLUSION

Increased dietary protein (from 12% to 14% DM), energy (from 65% to 70% DM), and RDP (from 55% to 65% crude protein [CP]) levels increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. The diet containing 14% DM dietary protein and 70% DM energy, which contained 55%, 60%, or 65% CP RDP optimally increased nutrient digestibility, ammonia concentration, total VFA levels, and microbial protein synthesis. Thus, feed based on these RDP:RUP ratios can optimize ruminant productivity.

Lactational performance, enteric gas emissions, and plasma amino acid profile of dairy cows fed diets with soybean or canola meals included on an equal protein basis

This study investigated the effects of feeding solvent-extracted canola meal (CM), extruded soybean meal (ESBM), or solvent-extracted soybean meal (SSBM) on an equivalent crude protein basis on performance, plasma AA profiles, enteric gas emissions, milk fatty acids, and nutrient digestibility in lactating dairy cows. Fifteen Holstein cows (95 ± 20 d in milk) were used in a replicated 3 × 3 Latin square design experiment with 3 periods of 28 d each. Treatments were 3 diets containing 17.1% CM, 14.2% ESBM, or 13.6% SSBM (dry matter basis). Vegetable oil was added (canola oil for CM or soybean oil for SSBM) to equalize the ether extract concentration of the diets. Rumen-protected Met was supplemented targeting digestible Met supply of 2.2% of metabolizable protein in all diets. Canola meal increased dry matter intake (DMI) by 5.9 and 8.9% in comparison with ESBM and SSBM, respectively. Milk urea nitrogen was lowest in CM, followed by SSBM, and was highest for ESBM. No differences were observed in feed efficiency, energy-corrected milk yield, and milk composition or component yields among treatments. Cows fed CM emitted less enteric CH4 per kg of DMI compared with both ESBM and SSBM, but CH4 emission intensity (CH4 per kg of energy-corrected milk) was similar among treatments. In summary, replacement of ESBM or SSBM with CM, on an equal crude protein basis, in the diet of lactating dairy cows enhanced DMI, but yields of energy-corrected milk and milk components and feed efficiency were similar among treatments.

Rapeseed pod meal can replace concentrate and enhance utilization of feed on in vitro gas production and fermentation characteristics

Rapeseed provides multi-products as human food and animal feed especially the oil and meal. Rapeseed oil and meal after extraction are nutritious and have been used in animal feeding. This study aimed at studying the effect of rapeseed pod meal as the replacement of concentrate (RPM) on in vitro gas and fermentation characteristics. Dietary treatments were imposed in a 2 × 6 factorial arrangement according to a completely randomized design (CRD). The first factor was two ratios of roughage to concentrate (R:C at 60:40, and 40:60) and the second factor was six levels of RPM at 0, 20, 40, 60, 80, and 100% of dietary substrate. The results revealed that the R:C ratio and RPM increased kinetics of gas production, in vitro degradability and improved rumen fermentation (P < 0.001). Ratio of R:C influenced (P < 0.05) on both protozoal population and methane production, while level of RPR did not. Both factors had influenced (P < 0.01) a, a + b, and c, as well as total gas production; nevertheless, there were no interactions (P > 0.05). Interestingly, both factors have greatly impacted on TVFA, C₃ (P < 0.01) and tended to reduce methane production as level of RPM replacement increased. In conclusion, RPM improved rumen fermentation and increased in vitro DM degradability, hence is potential for replacement of concentrate and effectively used for ruminant feeding.

Effects of replacing soybean meal with canola meal for lactating dairy cows fed 3 different ratios of alfalfa to corn silage

Previous research has demonstrated that feeding canola meal (CM) improves milk production and N utilization by lactating dairy cows when replacing solvent-extracted soybean meal (SBM). The objective of the present study was to evaluate whether CM would improve milk yield and components and N utilization, compared with SBM, at different ratios of alfalfa silage (AS) to corn silage (CS) fed to lactating dairy cows. Twenty-four multiparous Holstein cows averaging, at the beginning of the study (mean ± SD), 2.8 ± 0.9 parity, 684 ± 56 kg of BW, 102 ± 41 DIM, and 49 ± 4 kg milk/d, and 24 primiparous cows averaging (mean ± SD) 565 ± 46 kg of BW, 123 ± 30 DIM, and 40 ± 4 kg milk/d were blocked by parity and DIM. A cyclic changeover design with 4 replications of 2 blocks of treatments of 6 cows was used in an arrangement with 4 28-d periods. Dietary treatments were arranged in a 3 × 2 factorial design of 3 proportions of AS to CS as forage source (HAS = high AS, 50% AS to 10% CS; MAS = medium AS, 30% AS to 30% CS; LAS = low AS, 10% AS to 50% CS) and 2 protein supplements (CM vs. SBM). Diets were formulated to contain [dry matter (DM) basis]: 60% forage, 8 to 15% high-moisture corn, 2 to 5% soy hulls, 1.3% mineral-vitamin premix, 16% crude protein, and 31 to 33% NDF. Data from the last 2 weeks of each period were used to compute mean milk yield and composition, and efficiencies of feed conversion, for each cow in each period. Data for the other variables were collected during the last week of each period. All data were analyzed using the MIXED procedure of SAS (SAS Institute Inc., Cary, NC). Regardless of the forage source, replacing SBM with CM improved yields of milk, milk protein, and solids-not-fat. Moreover, milk urea nitrogen concentration and urinary excretion of total N (g/d) and urea N (% of total urinary N) decreased when CM replaced SBM. An interaction effect occurred between forage source and protein supplements for apparent total-tract digestibility, and, overall, this effect was due to small differences in ingredient and chemical compositions of the diets. In addition, these differences had a minor effect on cow performance. Yields of milk and milk components were greatest for cows fed 50% CS, intermediate for 30% CS, and lowest for 10% CS, indicating that, under the conditions of the present study, cows fed 50% CS in the diet (DM basis) had greater production compared with those fed 50% AS.

In vitro evaluation of Lactobacillus plantarum as direct-fed microbials in high-producing dairy cows diets

The objectives of this study were: 1) to compare the effects of live yeast (LY), yeast fermentation product (YFP), a mix of Lactobacillus acidophilus and Propionibacterium freudenreichii (MLP), and Lactobacillus plantarum included as additives in dairy cows’ diets on in vitro ruminal fermentation and gas production (GP); and 2) to evaluate the effects of L. plantarum as direct-fed microbials (DFM) in dairy cows’ diets on in vitro ruminal fermentation, GP, nutrient digestibility, and N metabolism. Three experiments were carried out: Exp. 1 had the objective to compare all additives regarding ruminal fermentation parameters: an Ankom GP system was used in a completely randomized design, consisting of four 48 h incubations, and eight replications per treatment. There were eight treatments: a basal diet without additive (CTRL) or with one of the following additives: LY, YFP, MLP, or L. plantarum at four levels (% of diet Dry Matter (DM)): 0.05% (L1), 0.10% (L2), 0.15% (L3), and 0.20% (L4). In Exp. 2, a batch culture was used to evaluate ruminal fermentation, and CO₂ and CH₄ production using the same treatments and a similar experimental design, except for having 16 replications per treatment. Based on Exp. 1 and 2 results, Exp. 3 aimed at evaluating the effects of the L. plantarum on ruminal true nutrient digestibility and N utilization in order to evaluate the use of L. plantarum as DFM. The treatments CTRL, MLP, L1, and L2 were used in a replicated 4 × 4 Latin square design using a dual-flow continuous culture system. Data were analyzed using linear and nonlinear regression; treatment means were compared through contrasts, and L treatments in Exp. 1 and 2 were tested for linear, quadratic, and cubic effects. In Exp. 1, all treatments containing additives tended to reduce OM digestibility as well as reduced total volatile fatty acids (VFA) concentration and total GP. The YFP had greater OM digestibility than LY, and MLP treatment had greater total VFA concentration compared to L. plantarum treatments. In Exp. 2, additives reduced CO₂ production, and there were no major differences in CH₄. In Exp. 3, all additives reduced NH₃-N concentration. In conclusion, pH and lactate concentration were not affected in all three experiments regardless of additive tested, suggesting that these additives may not improve ruminal fermentation by pH modulation; and L. plantarum may improve ruminal N metabolism when used as DFM in high-producing dairy cows’ diets, mainly by reducing NH₃-N concentration.

In vitro Digestibility, In situ Degradability, Rumen Fermentation and N Metabolism of Camelina Co-Products for Beef Cattle Studied with A Dual Flow Continuous Culture System of Camelina Co-Products for Beef Cattle

Simple Summary

Currently, vegetable protein sources such as soybean meal and rapeseed meal are expensive and with volatile prices. These economic circumstances are driving the research of potential new protein resources for beef cattle diets that can reduce the ration cost without compromising animal productive yields. As possible candidates, camelina meal and camelina expeller have been studied; they are co-products with a high protein percentage, obtained after oil extraction from the oil seeds of Camelina sativa. The objectives of this study were to characterize these camelina co-products and ascertain if they could be useful ingredients for beef cattle diets. The results indicate that the diets formulated with camelina meal and camelina expeller do not show differences in the efficiency of microbial protein synthesis compared to the current reference proteins, camelina meal diet being the most similar to soybean meal and rapeseed meal diets, and camelina expeller the diet with the highest fermentation potential. The results of soybean meal as an individual ingredient reveal more differences with camelina co-products. In vivo studies are necessary to draw conclusions, but in vitro results obtained suggest that camelina meal and camelina expeller are potential substitutes for rapeseed meal in beef cattle diets.

Abstract

Camelina meal (CM) and camelina expeller (CE) were compared with soybean meal (SM) and rapeseed meal (RM). Trial 1 consisted of a modified Tilley and Terry in vitro technique. Trial 2 was an in situ technique performed by incubating nylon bags within cannulated cows. Trial 3 consisted in dual-flow continuous culture fermenters. In Trial 1, CM, CE and RM showed similar DM digestibility and OM digestibility, and SM was the most digestible ingredient (p < 0.05). Trial 2 showed that CE had the numerically highest DM degradability, but CP degradability was similar to RM. Camelina meal had a DM degradability similar to SM and RM and had an intermediate coefficient of CP degradability. In Trial 3, CE diet tended to present a higher true OM digestibility than SM diet (p = 0.06). Total volatile fatty acids (VFA) was higher in CE and CM diets than in SM diet (p = 0.009). Crude protein degradation tended to be higher (p = 0.07), and dietary nitrogen flow tended to be lower (p = 0.06) in CE diet than in CM diet. The efficiency of microbial protein synthesis was not affected by treatment (p > 0.05). In conclusion, CE and CM as protein sources differ in CP coefficient of degradability but their results were similar to RM. More differences were detected with regard to SM.

Feeding Canola, Camelina, and Carinata Meals to Ruminants

Soybean meal (SBM) is a byproduct from the oil-industry widely used as protein supplement to ruminants worldwide due to its nutritional composition, high protein concentration, and availability. However, the dependency on monocultures such as SBM is problematic due to price fluctuation, availability and, in some countries, import dependency. In this context, oilseeds from the mustard family such as rapeseed/canola (Brassica napus and Brassica campestris), camelina (Camelina sativa), and carinata (Brassica carinata) have arisen as possible alternative protein supplements for ruminants. Therefore, the objective of this comprehensive review was to summarize results from studies in which canola meal (CM), camelina meal (CMM), and carinata meal (CRM) were fed to ruminants. This review was based on published peer-reviewed articles that were obtained based on key words that included the oilseed plant in question and words such as "ruminal fermentation and metabolism, animal performance, growth, and digestion". Byproducts from oil and biofuel industries such as CM, CMM, and CRM have been evaluated as alternative protein supplements to ruminants in the past two decades. Among the three plants reviewed herein, CM has been the most studied and results have shown an overall improvement in nitrogen utilization when animals were fed CM. Camelina meal has a comparable amino acids (AA) profile and crude protein (CP) concentration to CM. It has been reported that by replacing other protein supplements with CMM in ruminant diets, similar milk and protein yields, and average daily gain have been observed. Carinata meal has protein digestibility similar to SBM and its CP is highly degraded in the rumen. Overall, we can conclude that CM is at least as good as SBM as a protein supplement; and although studies evaluating the use of CMN and CRM for ruminants are scarce, it has been demonstrated that both oilseeds may be valuable feedstuff for livestock animals. Despite the presence of erucic acid and glucosinolates in rapeseed, no negative effect on animal performance was observed when feeding CM up to 20% and feeding CMN and CRM up to 10% of the total diet.

Unveiling the relationships between diet composition and fermentation parameters response in dual-flow continuous culture system: a meta-analytical approach

The objective of this study was to investigate the functional form of the relationship between diet composition (dietary crude protein [CP] and neutral detergent fiber [NDF]) and amount of substrate (fermenter dry matter intake [DMI]) with microbial fermentation end products in a dual-flow continuous culture system. A meta-analysis was performed using data from 75 studies. To derive the linear models, the MIXED procedure was used, and for nonlinear models, the NLMIXED procedure was used. Significance levels to fit the model assumed for fixed and random effects were P ≤ 0.05. Independent variables were dietary NDF, CP, and fermenter DMI, whereas dependent variables were total volatile fatty acids (VFA) concentration; molar proportions of acetate, propionate, and butyrate; true ruminal digestibilities of organic matter (OM), CP, and NDF; ammonia nitrogen (NH₃-N) concentration and flows of NH₃-N; non-ammonia nitrogen; bacterial-N; dietary-N; and efficiency of microbial protein synthesis (EMPS). Ruminal digestibilities of OM, NDF, and CP decreased as fermenter DMI increased (P < 0.04). Dietary NDF and CP digestibilities were quadratically associated (P < 0.01). Total VFA linearly increased as DMI increased (P < 0.01), exponentially decreased as dietary NDF increased (P < 0.01), and was quadratically associated with dietary CP (P < 0.01), in which total VFA concentration was maximized at 18% dietary CP. Molar proportion of acetate exponentially increased (P < 0.01) as dietary NDF increased. Molar proportion of propionate linearly increased and exponentially decreased as DMI and dietary NDF increased, respectively (P < 0.01). Bacterial-N quadratically increased and dietary-N exponentially increased as DMI increased (P < 0.01). Flows of bacterial-N and dietary-N linearly decreased as dietary NDF increased (P < 0.02), and dietary-N flow was maximized at 18% CP. The EMPS linearly increased as dietary CP increased (P < 0.02) and was not affected by DMI or dietary NDF (P > 0.05). In summary, increasing fermenter DMI increased total VFA concentration and molar proportion of propionate, whereas, dietary NDF increased the molar proportion of acetate. Dietary CP increased bacterial-N flow and was positively associated with NH₃-N concentration. Overall, the analysis of this dataset demonstrates evidences that the dual-flow continuous culture system provides valuable estimates of ruminal digestibility, VFA concentration, and nitrogen metabolism.

Effect of supplementing canola quality rapeseed mustard cake on the metabolic profile and quality of milk in crossbred cows

This study examined the comparative effect of incorporation of improved canola quality and high glucosinolates rapeseed mustard oil cake (RMC) in the supplement of crossbred cows on metabolic profile, thyroid hormones, milk yield and quality of milk. Lactating crossbred cows (18) were randomly divided into three groups of six each in a completely randomized design and allocated in three dietary supplements, viz. SBM, RMC and CM containing soybean meal (SBM), rapeseed mustard cake (RMC) and canola meal (CM), respectively as a major protein source for a period of 90 days. Daily intake of total dry matter and green fodder was comparable irrespective of dietary treatments. The supplement intake (kg/d) was significantly lower in the cows that were given RMC supplement compared to those given either SBM or CM supplement. Incorporation of CM in the supplement significantly increased daily and total milk yield (kg) as compared to RMC group. The milk thiocyanate level was significantly higher in RMC followed by CM and SBM groups. Blood-biochemical profile except significantly higher lactate dehydrogenase in RMC group remained comparable at different periods. Serum thiocyanate was significantly higher in RMC followed by CM and SBM. Serum T3 and T4 hormone levels were significantly lower in RMC fed group as compared to CM and SBM groups. It can be concluded that feeding of canola quality RMC (GSC5/6) may be used as complete replacement of soybean meal without any adverse effect on metabolic profile, thyroid hormones, milk quality and yield in crossbred cows.

Effects of lipopolysaccharide dosing on bacterial community composition and fermentation in a dual-flow continuous culture system

The objectives of this study were to evaluate the effects of lipopolysaccharide (LPS) dosing on bacterial fermentation and bacterial community composition (BCC), to set up a subacute ruminal acidosis (SARA) nutritional model in vitro, and to determine the best sampling time for LPS dosing in a dual-flow continuous culture system. Diets were randomly assigned to 6 fermentors in a replicated 3 × 3 Latin square with three 11-d experimental periods that consisted of 7 d for diet adaptation and 4 d for sample collection. Treatments were control diet (CON), wheat and barley diet (WBD) to induce SARA, and control diet + LPS (LPSD). Fermenters were fed 72 g of dry matter/d. The forage:concentrate ratio of CON was 65:35. The WBD diet was achieved by replacing 40% of dry matter of the CON diet with 50% ground wheat and 50% ground barley. The LPS concentration in LPSD was 200,000 endotoxin units, which was similar to that observed in cows with SARA. The SARA inducing and LPS dosing started at d 8. The BCC was determined by sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform (Illumina Inc., San Diego, CA). The LPSD and CON maintained pH above 6 for the entire experimental period, and the WBD kept pH between 5.2 and 5.6 for 4 h/d, successfully inducing SARA. Digestibility of neutral detergent fiber and crude protein in LPSD were not different from WBD but tended to be lower than CON. Lipopolysaccharide dosing had no effect on pool of VFA concentrations and profiles but decreased bacterial N; the pattern changes of VFA and LPS in LPSD started to increase and be similar to WBD 6 h after LPS dosing. Pool of LPS concentration was around 11-fold higher in WBD and 4-fold higher in LPSD than CON. In the solid fraction, the BCC of LPSD was different from WBD and tended to be different from CON. In the liquid fraction, the BCC was different among treatments. The LPS dosing increased the relative abundance of Succinimonas, Anaeroplasma, Succinivibrio, Succiniclasticum, and Ruminobacter, which are main gram-negative bacteria related to starch digestion. Our results suggest that LPS dosing does not affect pH alone. However, LPS could drive the development of SARA by affecting bacteria and bacterial fermentation. For future studies, samples are suggested to be taken 6 h after LPS dosing in a dual-flow continuous culture system.

Effect of replacing calcium salts of palm oil with camelina seed at 2 dietary ether extract levels on digestion, ruminal fermentation, and nutrient flow in a dual-flow continuous culture system

Camelina is a drought- and salt-tolerant oil seed, which in total ether extract (EE) contains up to 74% polyunsaturated fatty acids. The objective of this study was to assess the effects of replacing calcium salts of palm oil (Megalac, Church & Dwight Co. Inc., Princeton, NJ) with camelina seed (CS) on ruminal fermentation, digestion, and flows of fatty acids (FA) and AA in a dual-flow continuous culture system when supplemented at 5 or 8% dietary EE. Diets were randomly assigned to 8 fermentors in a 2 × 2 factorial arrangement of treatments in a replicated 4 × 4 Latin square design, with four 10-d experimental periods consisting of 7 d for diet adaptation and 3 d for sample collection. Treatments were (1) calcium salts of palm oil supplementation at 5% EE (MEG5); (2) calcium salts of palm oil supplementation at 8% EE (MEG8); (3) 7.7% CS supplementation at 5% EE (CS5); and (4) 17.7% CS supplementation at 8% EE (CS8). Diets contained 55% orchardgrass hay, and fermentors were fed 72 g of dry matter/d. On d 8, 9, and 10 of each period, digesta effluent samples were taken for ruminal NH₃, volatile fatty acids, nitrogen metabolism analysis, and long-chain FA and AA flows. Statistical analysis was performed using the MIXED procedure (SAS Institute Inc., Cary, NC). We detected an interaction between FA source and dietary EE level for acetate, where MEG8 had the greatest molar proportion of acetate. Molar proportions of propionate were greater and total volatile fatty acids were lower on CS diets. Supplementation of CS decreased overall ruminal nutrient true digestibility, but dietary EE level did not affect it. Diets containing CS had greater biohydrogenation of 18:2 and 18:3; however, biohydrogenation of 18:1 was greater in MEG diets. Additionally, CS diets had greater ruminal concentrations of trans-10/11 18:1 and cis-9,trans-11 conjugated linoleic acid. Dietary EE level at 8% negatively affected flows of NH₃-N (g/d), nonammonia N, and bacterial N as well as the overall AA outflow. However, treatments had minor effects on individual ruminal AA digestibility. The shift from acetate to propionate observed on diets containing CS may be advantageous from an energetic standpoint. Moreover, CS diets had greater ruminal outflow of trans-10/11 18:1 and cis-9,trans-11 conjugated linoleic acid than MEG diets, suggesting a better FA profile available for postruminal absorption. However, dietary EE at 8% was deleterious to overall N metabolism and AA outflow, indicating that CS can be fed at 5% EE without compromising N metabolism.

Nutritional evaluation and ruminal fermentation patterns of kochia compared with alfalfa and orchardgrass hays and ephedra and cheatgrass compared with orchardgrass hay as alternative arid-land forages for beef cattle in two dual-flow continuous culture system experiments

The objective was to evaluate the ruminal fermentation patterns of forage kochia (FK) compared with alfalfa hay (AH) and orchardgrass hay (OH) (Exp. 1), and ephedra (EPH) and immature cheatgrass (CG) compared with OH (Exp. 2), using a dual-flow continuous culture system. Two in vitro experiments were conducted, and in each experiment, treatments were randomly assigned to six dual-flow fermenters (1,223 ± 21 mL) in a replicated 3 × 3 Latin square design, with three consecutive periods of 10 d each, consisting of 7 d for diet adaptation and 3 d for sample collection. Each fermenter was fed a total of 72 g/d (DM basis) and treatments were as follows: Exp. 1: 1) 100% OH, 2) 100% AH, and 3) 100% dried FK. Exp. 2: 1) 100% OH, 2) 100% dried CG, and 3) 100% dried EPH. On day 8, 9, and 10, samples of solid and liquid effluent from each fermenter were taken for digestibility analysis, and subsamples were collected for NH3-N, VFA, and bacterial N determinations. Data were analyzed using the MIXED procedure of SAS. In Exp. 1, treatments did not affect DM, OM, and NDF digestibilities, total VFA and molar proportions of acetate, propionate, butyrate, and branched-chain VFA. True CP digestibility, ruminal NH3-N concentration, and total N, NH3-N, NAN, and dietary N flows (g/d) were greater (P < 0.05) for FK compared with the other forages. However, treatments did not affect bacterial efficiency. In Exp. 2, DM, OM, and CP digestibilities were greater (P = 0.01) for EPH, and NDF digestibility was greater (P < 0.05) for EPH and CG compared with OH. Ephedra had the highest (P < 0.05) pH and acetate:propionate ratio and the lowest (P < 0.05) total VFA concentration. Total VFA, ruminal NH3-N concentration, and NH3-N flow (g/d) were highest (P < 0.05) for CG. Total N flow and bacterial efficiency were highest (P < 0.05) for OH and CG, while the flows (g/d) of NAN, bacterial N, and dietary N were greater (P < 0.05) for OH compared with the other forages. Results indicate that when compared with AH and OH (Exp. 1), FK has similar ruminal fermentation patterns and may be an adequate alternative for beef cattle producers. Furthermore, when compared with OH (Exp. 2), immature CG may also be an adequate forage alternative. This is especially important for areas in which conventional forages may not grow well such as the U.S. arid-land. However, EPH should not be used as the sole forage due to its poor ruminal fermentation as evidenced by the lowest total VFA concentration and propionate molar proportion.

Effects of replacing soybean meal with canola meal or treated canola meal on ruminal digestion, omasal nutrient flow, and performance in lactating dairy cows

Extrusion treated canola meal (TCM) was produced in an attempt to increase the rumen-undegraded protein fraction of canola meal (CM). The objective of this study was to evaluate the effects of replacing soybean meal (SBM) with CM or TCM on ruminal digestion, omasal nutrient flow, and performance in lactating dairy cows. To assess performance, 30 multiparous Holstein cows averaging (mean ± SD) 119 ± 23 d in milk and 44 ± 7 kg of milk/d and 15 primiparous cows averaging 121 ± 19 d in milk and 34 ± 6 kg of milk/d were blocked in a randomized complete block design with a 2-wk covariate period and 12-wk experimental period (experiment 1). Dietary ingredients differed only in protein supplements, which were SBM, CM, or TCM. All diets were formulated to contain (dry matter basis) 30% alfalfa silage, 30% corn silage, 4% soy hulls, 2.4% mineral-vitamin premix, and 16% CP. The SBM diet contained 25% high-moisture shelled corn and 8.6% SBM; the canola diets contained 22% high-moisture shelled corn and either 11.2% CM or 11.4% TCM. To assess ruminal digestion and omasal nutrient flow, 6 rumen-cannulated cows were blocked into 2 squares of 3 cows and randomly assigned within blocks to the same 3 dietary treatments as in experiment 1 in a replicated 3 × 3 Latin square design (experiment 2). Data were analyzed using the MIXED procedure of SAS (SAS Institute, Cary, NC). Orthogonal contrasts were used to compare effects of different protein supplements: SBM versus CM + TCM and CM versus TCM. In experiment 1, compared with SBM, apparent total-tract digestibilities of dry matter and nutrients were greater in cows fed both CM diets, and there was a tendency for nutrient digestibilities to be higher in cows fed CM compared with TCM. Diets did not affect milk yield and milk components; however, both canola diets decreased urinary urea N (% of total urinary N), fecal N (% of total N intake), and milk urea N concentration. In experiment 2, compared with SBM, both canola diets increased N intake and tended to increase rumen-degraded protein supply (kg/d) and N truly digested in the rumen (kg/d). Diets did not affect ruminal digestibility, efficiency of microbial protein synthesis, and rumen-undegraded protein flow among diets. Results from this experiment indicate that replacing SBM with CM or TCM in diets of lactating cows improved digestibility and may reduce environmental impact. Moreover, under the conditions of the present study, treating CM by extrusion did not improve CM utilization.

Camelina Seed Supplementation at Two Dietary Fat Levels Change Ruminal Bacterial Community Composition in a Dual-Flow Continuous Culture System

This experiment aimed to determine the effects of camelina seed (CS) supplementation at different dietary fat levels on ruminal bacterial community composition and how it relates to changes in ruminal fermentation in a dual-flow continuous culture system. Diets were randomly assigned to 8 fermenters (1,200–1,250 mL) in a 2 × 2 factorial arrangement of treatments in a replicated 4 × 4 Latin square with four 10-day experimental periods that consisted of 7 days for diet adaptation and 3 days for sample collection. Treatments were: (1) no CS at 5% ether extract (EE, NCS5); (2) no CS at 8% EE (NCS8); (3) 7.7% CS at 5% EE (CS5); and (4) 17.7% CS at 8% EE (CS8). Megalac was used as a control to adjust EE levels. Diets contained 55% orchardgrass hay and 45% concentrate, and fermenters were equally fed a total of 72 g/day (DM basis) twice daily. The bacterial community was determined by sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform. Sequencing data were analyzed using mothur and statistical analyses were performed in R and SAS. The most abundant phyla across treatments were the Bacteroidetes and Firmicutes, accounting for 49 and 39% of the total sequences, respectively. The bacterial community composition in both liquid and solid fractions of the effluent digesta changed with CS supplementation but not by dietary EE. Including CS in the diets decreased the relative abundances of Ruminococcus spp., Fibrobacter spp., and Butyrivibrio spp. The most abundant genus across treatments, Prevotella, was reduced by high dietary EE levels, while Megasphaera and Succinivibrio were increased by CS supplementation in the liquid fraction. Correlatively, the concentration of acetate was decreased while propionate increased; C18:0 was decreased and polyunsaturated fatty acids, especially C18:2 n-6 and C18:3 n-3, were increased by CS supplementation. Based on the correlation analysis between genera and fermentation end products, this study revealed that CS supplementation could be energetically beneficial to dairy cows by increasing propionate-producing bacteria and suppressing ruminal bacteria associated with biohydrogenation. However, attention should be given to avoid the effects of CS supplementation on suppressing cellulolytic bacteria.