Ruminal Protozoa Research Articles

Detoksifikasi Mikotoksin Melalui Optimalisasi Fungsi Rumen dengan Pemberian Ragi (MYCOTOXIN DETOXIFICATION THROUGH OPTIMIZATION THE RUMEN FUNCTION BY YEAST)

Mycotoxins are toxic metabolites produced by some fungal species commonly found in food and feed,particularly in cereals. In intensive production systems, dairy cattle are commonly fed with cereal-richdiets and, consequently, are more exposed to micotoxins. Besides, such diet is often associated with ahigher risk of rumen acidosis which can also affect the performance and the helath of animal. In addition,the efficacy of microbial detoxification can be reduced during acidosis. For instance, some authors observeda decrease in the number of protozoa that are responsible for the degradation of some mycotoxins. Anotherconsequence of acidosis is the potential modification of ruminal absorption of mycotoxins, which until nowhas received scarce attention. Yeast Saccharomyces cerevisiae, probiotic additives have been shown toreduce the post-feeding drop in rumen pH and to increase the number of ruminal protozoa. This effect canbe positive in reducing the absorption and toxicity of mycotoxins in ruminantia.

Effects of a specific blend of essential oils on apparent nutrient digestion, rumen fermentation and rumen microbial populations in sheep fed a 50:50 alfalfa hay:concentrate diet.

ObjectiveAn experiment was conducted to investigate the effects of a specific mixture of essential oils (MEO), containing thyme, clove and cinnamon EO, on rumen microbial fermentation, nutrient apparent digestibility and blood metabolites in fistulated sheep.MethodsSix sheep fitted with ruminal fistulas were used in a repeated measurement design with two 24-d periods to investigate the effect of adding MEO at 0 (control), 0.8, and 1.6 mL/d on apparent nutrient digestibility, rumen fermentation characteristics, rumen microbial population and blood chemical metabolites. Animals were fed with a 50:50 alfalfa hay:concentrate diet.ResultsRuminal pH, total volatile fatty acids (VFA) concentration, molar proportion of individual VFA, acetate: propionate ratio and methane production were not affected with MEO. Relative to the control, Small peptides plus amino acid nitrogen and large peptides nitrogen concentration in rumen fluid were not affected with MEO supplementation; while, rumen fluid ammonia nitrogen concentration at 0 and 6 h after morning feeding in sheep fed with 1.6 mL/d of MEO was lower (p<0.05) compared to the control and 0.8 mL/d of MEO. At 0 h after morning feeding, ammonia nitrogen concentration was higher (p<0.05) in sheep fed 0.8 mL/d of MEO relative to 1.6 mL/d and control diet. Ruminal protozoa and hyper ammonia producing (HAP) bacteria counts were not affected by addition of MEO in the diet. Relative to the control, no changes were observed in the red and white blood cells, hemoglobin, hematocrit, glucose, beta-hydroxybutyric acid, cholesterol, total protein, albumin, blood urea nitrogen and aspartate aminotransferase and alanine aminotransferase concentration. Apparent total tract digestibility of dry matter, crude proten, organic matter, and neutral detergent fiber were not influenced by MEO supplementation.ConclusionThe results of the present study suggested that supplementation of MEO may have limited effects on apparent nutrient digestibility, ruminal fermentation and protozoa and HAP bacteria count, blood cells and metabolites.

Effects of Bentonite on Weight Gain, Feed Consumption, Blood Metabolites and Ruminal Protozoa in Dairy Calves

In order to ascertain the effects of addition of bentonite as a pelleting medium in the feed mixture for calves, fourteen 30d-old calves were randomly distributed into two equal groups (CON and EXP). From 30 to 120d of age the EXP group was fed a feed mixture containing 1.5% of natural bentonite while the CON group was fed the same pellets without added bentonite. Body weight was determined before and at the end of the trial. Feed intake was measured daily. Health status was monitored daily. Blood and rumen content samples were taken at 50 and 90d of experiment and analyzed for select parameters. The addition of bentonite had no effect (P>0.05) on average daily gain, feed intake and health. Blood pH, total number and motility of ruminal protozoa in the EXP group were significantly (P<0.001, P<0.05 and P<0.05; respectively) higher than in CON group at both the periods. At 120d of age the EXP calves had a significantly (P<0.05, P<0.05 and P<0.01; respectively) higher serum total protein, albumin and triglyceride concentrations and lower iron and IGF-I (P<0.05 and P<0.01, respectively) concentrations than respective controls values. It is concluded that the use of pelleted feed containing bentonite tended to improve growth of calves as well as the activity of protozoa in the rumen. Additionally, the results indicate a positive influence of the function of hepatocytes concomitant to a reduction in serum iron and IGF-I concentrations.

Protozoários ruminais de novilhos de corte criados em pastagem tropical durante o período seco

Protozoários do rúmen podem representar 40% do nitrogênio total e 60% do produto final da fermentação e apresentam atividade celulolítica. Neste estudo, objetivou-se quantificar e identificar as populações de protozoários no rúmen de novilhos, criados exclusivamente em pastagem, durante o período seco do ano, no Norte de Minas Gerais. Amostras do suco ruminal de 36 novilhos mestiços Nelore foram coletadas diretamente do rúmen, após o abate, durante o inicio, meio ou fim do período de estiagem. Para conservação dos protozoários, 1 mL do suco ruminal foi diluído em 9 mL de solução de formaldeido a 10%. Posteriormente, foram realizadas diluições decimais em solução salina e contagem de protozoários pequenos, médios e grandes em câmara de Sedgewick Rafter. As concentrações de protozoários foram transformadas em log10 (x+1) e submetidas à análise de variância e as médias comparadas com teste de Duncan. As frequências dos gêneros foram comparadas com o teste do qui-quadrado. As médias da concentração total e de pequenos e médios protozoários diminuíram significativamente com o decorrer do período seco; entretanto, os grandes protozoários não apresentaram alterações na concentração média durante os três períodos avaliados. Foram identificados 7749 protozoários, pertencentes a 17 gêneros diferentes. Observou-se que os gêneros Charonina e Entodinium apresentaram alta ocorrência no início, meio e final do período da seca (p&lt;0,05), indicando a participação desses ciliados em bovinos alimentados exclusivamente a pasto, durante esse período do ano.

Abundance and diversity of rumen protozoa in lambs fed Gliricidia sepium silage

The objective of this study was to evaluate changes in ruminal protozoa in lambs after partial replacement of feed concentrates in their diets with Gliricidia sepium silage. Twenty-four male Santa Ines lambs with an average initial weight of 14.5 kg were used. The experimental design was completely randomized, with four treatments and six replications. Treatments (given as a percentage of dry matter) were as follows: control - corn silage (600 g kg-1 as fed) + concentrate (400 g kg-1 as fed); GS133 - corn silage (600 g kg-1 as fed) + G. sepium silage (133 g kg-1as fed) + concentrate (267 g kg-1 as fed); GS267 - corn silage (600 g kg-1 as fed) + G. sepium silage (267g kg-1as fed) + concentrate (133 g kg-1 as fed); and GS400 - corn silage (600 g kg-1 as fed) + G. sepium silage (400 g kg-1as fed). Samples of rumen contents were obtained at slaughter, and analysis revealed the presence of nine genera of rumen protozoa that were present in all animals, with the exception of Enoploplastron and Eremoplastron. There were no significant differences in the average total numbers of rumen ciliates or in the composition of species between lambs. Inclusion of up to 400 g kg-1 (as fed) G. sepium silage in the diet of lambs does not affect the diversity or density of rumen protozoa.

Effects of Anthelmintic Plant Extracts on Ruminal Fermentation Characteristics, Bacterial Diversity and Methane Production in vitro

The objective of this study was to know the in vitro effects of supplemental anthelmintic plant extracts on the inhibition of protozoa for reducing methane production in the rumen. A fistulated Holstein cow was used as a donor of rumen fluid. The plant extracts (Lonicera japonica, Zanthoxylum piperitum, Pyrethrum, Torreya nucifera, Ruta graveolens) known to have anthelmintic effect were added to the in vitro fermentation bottles containing the rumen fluid and medium. The rumen protozoal population was depressed by the addition of Pyrethrum, Torreya nucifera and Ruta graveolens. The methane production was also significantly (p<0.05) reduced by addition of Pyrethrum (2.20 ml/g DM), Torreya nucifera (2.36 ml/g DM) and Ruta graveolens (2.20 ml/g DM). The microbial growth in the treatments of Ruta graveolens or Zanthoxylum piperitum was the greatest after 12 h and 24 h incubations, respectively. The results of this study indicated that anthelmintic plant extracts appeared to reduce methane production by inhibition of ruminal protozoa related with the methanogens living endosymbiotic in protozoal cells.

Influence of Salix babylonica and Leucaena leucocephala leaf extracts on ruminal fermentation characteristics, urinary purine derivative excretion and microbial protein synthesis of lambs

Sixteen growing Katahdin×Pelibuey lambs (24±0.3kg body weight) were used to study the effects of oral administration of extracts of Salix babylonica (SB) and Leucaena leucocephala (LL) leaves on ruminal pH, total and individual volatile fatty acids (VFA) and NH3-N concentrations, as well as ruminal protozoal counts, urinary purine derivatives (PD) excretion and estimated microbial protein synthesis. Lambs were fed a total mixed ration (TMR) containing 219 and 141gkg−1 of CP and NDF, respectively. Four treatments (4lambs/treatment) were Control (no extract added), SB (SB extract at 30mld−1), LL (LL extract at 30mld−1) and SBLL (mixture of SB at 15mld−1+LL at 15mld−1). Extracts were administered orally to each lamb before the morning meal daily. Measurements were on days 22 (P1), 43 (P2) and 63 (P3) of the experiment. Ruminal pH increased (P=0.014) with SBLL extract and decreased with SB. The ratio of acetate to propionate was higher (P=0.042) with SBLL compared to the control. Ruminal NH3-N concentration was not affected by extract administration (P=0.309) or experimental period (P=0.087). Protozoal counts were not affected (P=0.489) by extract addition but decreased (P<0.001) in P3 compared with P1 and P2. Uric acid concentration increased (P<0.001) with individual extracts of SB and LL compared with the control or SBLL. Excretion of other purine derivatives (allantoin, xanthine, and hypoxanthine), creatinine and microbial protein synthesis were not changed (P>0.05) by extracts administration. Overall, oral administration of S. babylonica and L. leucocephala extracts, or their 1:1 mixture, to lambs for 63d had only minor effects on ruminal fermentation, urinary purine derivative excretion and microbial protein synthesis.

Fluorescence in situ hybridization probing of protozoal Entodinium spp. and their methanogenic colonizers in the rumen of cattle fed alfalfa hay or triticale straw

To develop and test a fluorescence in situ hybridization (FISH) based technique and to identify and quantify simultaneously those methanogenic populations colonizing Entodinium spp. in the rumen of cows fed different forages. New FISH probes targeting protozoal Entodinium spp. were designed and used together with FISH probes for methanogens in the cow rumen. The composition and relative abundance of methanogenic populations colonizing Entodinium simplex-, E. caudaum- and Entodinium furca-related populations were similar. Methanogens including Methanobrevibacter thaueri, Methanobrevibacter millerae and Methanobrevibacter smithii, and members of Methanomicrobium and Methanosphaera were generally the predominant colonizers of protozoa, regardless of the forage fed to cattle. Individual animals appeared to differ in which ruminal methanogenic populations colonized each of the individual Entodinium spp. Simultaneous FISH probing is shown here to be a reliable and effective approach to investigate the dynamics of symbiotic relationships between ruminal protozoa and methanogens at a single cell level. Phylogenetically closely related Entodinium spp. were colonized by similar methanogenic populations regardless of the forage fed. This is the first report of the methanogenic archaeal populations that specifically colonize Entodinium spp. as identified using simultaneous FISH probing.

Effects of feeding lauric acid on ruminal protozoa numbers, fermentation, and digestion and on milk production in dairy cows1

The objectives of this study were 1) to determine the level of lauric acid (LA) addition to the diet necessary to effectively suppress ruminal protozoa (RP) to the extent observed when a single dose was given directly into the rumen, 2) to assess LA effects on production and ruminal metabolism, and 3) to determine the time needed for RP to reestablish themselves after LA is withdrawn from the diet of lactating dairy cows. In Exp. 1, 2 Holstein cows fitted with ruminal cannulae were used in a split-plot design pilot study. Both cows consumed the same level of LA, starting with 0 g/d and increasing to 129, 270, and 438 g/d mixed into the diet. Diets were fed as total mixed ration (TMR) and contained (DM basis) 30% corn silage, 30% alfalfa silage, and 40% concentrate. Lauric acid intake linearly decreased DMI (P = 0.03), RP numbers (P < 0.01), ruminal acetate molar proportion (P = 0.03), and ruminal ammonia concentration (P = 0.03). Lauric acid intake linearly increased ruminal valerate molar proportion (P = 0.02). A quadratic response of LA consumption was observed on total ruminal VFA concentration (P < 0.01) and propionate molar proportion (P < 0.01), with maximum responses at 270 g/d of LA intake. A quadratic response of LA consumption was also observed on total ruminal free amino acid (TAA) concentration (P < 0.01), with minimum concentration at 270 g/d of LA intake. After withdrawing the greatest LA dose from the diet, RP returned to their original numbers in 12 d. In Exp. 2, 48 multiparous Holstein cows (8 with ruminal cannulae) were blocked by days in milk into 12 blocks of 4 cows (2 blocks of cannulated cows) and randomly assigned within replicated 4 × 4 Latin squares to balanced dietary treatment sequences. Diets were fed as TMR and contained (DM basis) 36% corn silage, 29% alfalfa silage, and 35% concentrate, and LA intake levels were 0, 220, 404, and 543 g/d mixed in the TMR. In Exp. 2, LA linearly reduced RP (P < 0.01), ruminal ammonia (P < 0.01), and total free AA concentration (P < 0.01); however, dietary LA also linearly decreased DM intake (P < 0.01). Intake of LA linearly reduced ruminal total VFA concentration (P < 0.01); DM, OM, NDF, and CP digestibility (P < 0.01); and milk production and milk components (P < 0.01). Therefore, LA does not appear to be a feasible RP suppressant for feeding in practical diets.

Rumen bacterial, archaeal, and fungal diversity of dairy cows in response to ingestion of lauric or myristic acid1

The objective of this experiment, part of a larger study, was to investigate changes in rumen bacterial, archaeal, and fungal diversity in cows fed medium-chain saturated fatty acids. In the main study, 6 lactating dairy cows were dosed intraruminally with 240 g/(cow · d) of stearic (SA, control), lauric (LA), or myristic (MA) acid in a replicated 3 × 3 Latin square design trial. Experimental periods were 28 d, and cows were transfaunated between periods. Lauric acid decreased protozoal counts in the rumen by 96% compared with SA and MA (compared with SA, MA had no effect on ruminal protozoa). Whole ruminal contents samples were collected 2, 4, 6, 8, 10, 14, 18, and 24 h after the morning feeding on d 23 of each experimental period, stored frozen, and later composited by cow and period for microbial profile analyses, which involved tag-encoded flexible (FLX) amplicon pyrosequencing to provide diversity analyses of gastrointestinal bacterial, archaeal, and fungal populations of the cattle. The LA treatment, either directly or through its effect on protozoa, had a profound effect on the microbial ecology of the rumen. Ruminal populations of Prevotella, Bacteroides, and Enterorhabdus were decreased (P = 0.04 to P < 0.001) by more than 2-fold in LA treatments compared with SA, and Clostridium populations were decreased (P = 0.01) in LA- compared with MA-treated cows. The proportion of Ruminococcus was not affected by treatment, although the LA treatment had the least proportion of Ruminococcus. Proportions of Eubacterium, Butyrivibrio, Olsenella, and Lactobacillus genera were increased (P = 0.03 to 0.01) by LA compared with MA or SA. The LA treatment, possibly through its effect on protozoa physically associated with archaea, resulted in an increase (P = 0.01) in the archaeal methanogenic genus Methanosphaera and a decrease (P = 0.01) in Methanobrevibacter. Few changes in fungal populations caused by treatment were detected. Collectively, results indicate that LA, either through antiprotozoal or direct antimicrobial effects, altered bacterial and archaeal populations in the rumen of dairy cows, but effects on fungal populations were not clear.

Interaction of unsaturated fat or coconut oil with monensin in lactating dairy cows fed 12 times daily. II. Fatty acid flow to the omasum and milk fatty acid profile

Feeding animal-vegetable (AV) fat or medium-chain fatty acids (FA) to dairy cows can decrease ruminal protozoal counts. However, combining moderate to large amounts of AV fat with monensin (tradename: Rumensin, R) could increase the risk for milk fat depression (MFD), whereas it is not known if diets supplemented with coconut oil (CNO; rich in medium-chain FA) with R would cause MFD. In a 6 × 6 Latin square design with a 2 × 3 factorial arrangement of treatments, 6 rumen-cannulated cows were fed diets without or with R (12 g/909kg) and either control (no fat), 5% AV fat, or 5% CNO. Diets were balanced to have 21.5% forage neutral detergent fiber, 16.8% crude protein, and 42% nonfiber carbohydrates. Omasal flows of FA were characterized by an increased percentage of trans 18:1 for AV fat and CNO diets compared with the control, a higher percentage of 12:0 and 14:0 for CNO, and higher cis 18:1 for AV fat. Milk FA composition reflected the changes observed for omasal FA digesta flow. The de novo FA synthesis in the mammary gland was decreased by the main effects of R compared without R (averaged over fat treatments) and for added fat (AV fat and CNO) versus control (averaged over R). The percentages of 6:0, 8:0, and 10:0 in milk fat were lower for R and for AV fat and CNO compared with the control. The percentage of trans 18:1 FA in milk fat also higher for AV fat and CNO compared with the control. Against our hypotheses, the feeding of CNO did not prevent MFD, and few interactions between R and fat source were detected. The feeding of CNO did compromise ruminal biohydrogenation, with accumulation of trans 18:1 in the rumen and in milk fat.

Ruminal protozoal contribution to the duodenal flow of fatty acids following feeding of steers on forages differing in chloroplast content

Ruminant products are criticised for their SFA content relative to PUFA, although n-6:n-3 PUFA is desirable for human health (<4). Rumen protozoa are rich in unsaturated fatty acids due to engulfment of PUFA-rich chloroplasts. Increasing the chloroplast content of rumen protozoa offers a potentially novel approach to enhance PUFA flow to the duodenum and subsequent incorporation into meat and milk. We evaluated protozoal contribution to duodenal n-3 PUFA flow due to intracellular chloroplast content. A total of six Holstein×Friesian steers were fed, in a two-period changeover design, either straw:concentrate (S:C, 60:40; DM basis; S:C, low chloroplast) or fresh perennial ryegrass (PRG; high chloroplast). Following 12d adaptation to diet, ruminal protozoal and whole duodenal samples were obtained. N and fatty acid content of whole duodenum and rumen protozoal samples were assessed and protozoal 18S rDNA quantitative PCR performed, enabling calculation of protozoal N flow. The ratio of individual fatty acids:N in rumen protozoal samples was calculated to obtain protozoal fatty acid flows. Based on total fatty acid flow, contribution (%) of protozoa to individual fatty acid flows was calculated. Protozoal fatty acid data and microscopical observations revealed that protozoa were enriched with 18:3n-3 following PRG feeding, compared with the S:C diet, due to increased intracellular chloroplast content. However, duodenal protozoal 18S rDNA concentration post PRG feeding was low, indicating rumen retention of the protozoa. Nutrition influences the 18:3n-3 content of protozoa; the challenge is to increase protozoal flow to the small intestine, while maintaining sustainable rumen densities.

Effect of mycotoxin deactivator product supplementation on dairy cows

A total mixed ration (TMR) containing a blend of feedstuffs naturally contaminated with harmful mycotoxins was fed for 84 days to 24 primiparous and multiparous Holstein–Friesian × local dairy cows in a randomised complete block design. The dietary treatments consisted of a contaminated TMR diet plus various levels of the mycotoxin deactivator product (MDP) (0, 15, 30 or 45 g/head.day). Deoxynivalenol (DON), fumonisin B1 (FB1), zearalenone (ZON) and ochratoxin A (OTA) were found in the TMR at levels up to 720, 701, 541 and 501 μg/kg, whereas aflatoxin B1 (AfB1) and T-2 toxin (T-2) were found in the TMR at levels of 38 and 270 μg/kg, respectively. Rumen microbial ecology, ruminal volatile fatty acid (VFA) concentrations, ruminal microorganism populations, feed intake, total tract digestibility, milk yield, milk composition and serum immunoglobulin (Ig) concentrations were measured. The results revealed that the ruminal pH, ruminal ammonia nitrogen (NH3-N) concentration, total ruminal VFA concentrations and ruminal bacterial counts were significantly (P &lt; 0.05) higher in supplemented than in non-supplemented cows. Ruminal protozoal counts were significantly (P &lt; 0.05) lower in supplemented than in non-supplemented cows. DM intake, and digestibility of crude protein (CP) and neutral detergent fibre (NDF) were significantly (P &lt; 0.05) higher in supplemented than in non-supplemented cows. Serum IgA concentrations were significantly (P &lt; 0.05) higher in supplemented than in non-supplemented cows. Milk yield and milk protein were significantly (P &lt; 0.05) higher in supplemented than in non-supplemented cows. On the basis of this experiment, it can be concluded that milk production and feed intake can be increased with the addition of MDP to cow diet in the presence of mycotoxins. These increases were accompanied by decreases in the negative effects of mycotoxins on rumen and immune function.

Effects of dietary protein concentration and coconut oil supplementation on nitrogen utilization and production in dairy cows

The objective of this study was to investigate the effect of metabolizable protein (MP) deficiency and coconut oil supplementation on N utilization and production in lactating dairy cows. The hypothesis of the study was that a decrease in ruminal protozoal counts with coconut oil would increase microbial protein synthesis in the rumen, thus compensating for potential MP deficiency. The experiment was conducted for 10 wk with 36 cows (13 primiparous and 23 multiparous), including 6 ruminally cannulated cows. The experimental period, 6 wk, was preceded by 2-wk adaptation and 2-wk covariate periods. Cows were blocked by parity, days in milk, milk yield, and rumen cannulation and randomly assigned to one of the following diets: a diet with a positive MP balance (+44g/d) and 16.7% dietary crude protein (CP) concentration (AMP); a diet deficient in MP (−156g/d) and 14.8% CP concentration (DMP); or DMP supplemented with approximately 500g of coconut oil/head per day (DMPCO). Ruminal ammonia tended to be greater and plasma urea N (20.1, 12.8, and 13.1mg/dL, for AMP, DMP, and DMPCO diets, respectively) and milk urea N (12.5, 8.3, and 9.5mg/dL, respectively) were greater for AMP compared with DMP and DMPCO. The DMPCO diet decreased total protozoa counts (by 60%) compared with DMP, but had no effect on the methanogens profile in the rumen. Total tract apparent digestibility of dry matter and CP was decreased by DMP compared with AMP. Fiber digestibility was lower for both DMP and DMPCO compared with AMP. Urinary N excretion was decreased (by 37%) by both DMP and DMPCO compared with AMP. The DMP and DMPCO diets resulted in greater milk N efficiency compared with AMP (32.0 and 35.1 vs. 27.6%, respectively). Milk yield was decreased by both DMP and DMPCO compared with AMP (36.2, 34.4, and 39.3kg/d, respectively) and coconut oil supplementation suppressed feed intake and caused milk fat depression. Coconut oil supplementation decreased short-chain fatty acid (C4:0, C6:0, and C8:0) concentration and increased medium-chain (C12:0 and C14:0) and total trans fatty acids in milk. Overall, the MP-deficient diets decreased N losses, but could not sustain milk production in this study. Coconut oil decreased feed intake and similar to DMP, suppressed fiber digestibility. Despite decreased protozoal counts, coconut oil had no effect on the methanogen population in the rumen.

Monensin and protein supplements on methane production and rumen protozoa in bovine fed low quality forage

This study aimed at evaluating the effect of sodium monensin and protein supplementation in the enteric methane production and the population of ruminal protozoa in bovine fed Brachiaria brizantha Marandu cultivar hay. The treatments were: mineralized salt, mineralized salt with monensin, proteinenriched salt and protein-enriched salt with monensin. The experimental outline was in a 4 x 4 Latin square. The protein supplementation increased the dry matter intake and the total concentrations of rumen ciliate protozoa. Monensin eliminated the rumen fauna and reduced the methane production. Methane production was 19.13; 15.73; 24.35 and 11.52 g/kg of ingested DM when mineralized salt, mineralized salt with monensin, protein-enriched salt and protein-enriched salt with monensin were supplied, respectively. The association between the inputs allows for a reduction in the methane production without a reduction in dry matter intake.

Feeding sunflower oil to partially defaunate the rumen increases nitrogen retention, urea-nitrogen recycling to the gastrointestinal tract and the anabolic use of recycled urea-nitrogen in growing lambs

The objective of the present study was to delineate how interactions between feeding sunflower oil (SFO) to partially defaunate the rumen and altering dietary ruminally fermentable carbohydrate may alter urea-N kinetics and N metabolism in lambs. In a 4 × 4 Latin square with a 2 × 2 factorial arrangement of treatments, four Suffolk ram lambs (61·5 (se 4·0) kg) were used. Treatments were 0 ( - SFO) v. 6 % (+SFO) SFO and dry-rolled barley (DRB) v. pelleted barley (PB). N balance was measured over 4 d, with concurrent measurement of urea-N kinetics using continuous intra-jugular infusions of [(15)N(15)N]urea. Feeding SFO decreased (P = 0·001) ruminal protozoa and NH3-N concentrations. Urinary N excretion was lower (P = 0·003), and retained N was higher (P = 0·002) in +SFO lambs compared with - SFO lambs. Endogenous production of urea-N (urea-N entry rate; UER) was similar across treatments. Urea-N transfer to the gastrointestinal tract (GIT) (GIT entry rate; GER), expressed as absolute amounts (16·4 v. 13·1 g/d) or as a proportion of the UER (0·693 v. 0·570), its anabolic use (9·0 v. 6·0 g/d) and microbial N supply (14·6 v. 10·9 g/d) were higher (P ≤ 0·001) in +SFO lambs compared with -SFO lambs. As a proportion of the UER, GER was higher, whereas urinary urea-N loss was lower, in lambs fed PB compared with those fed DRB (P = 0·01). In summary, feeding SFO increased urea-N recycling to the GIT and microbial non-NH(3)-N supply, thus providing new evidence that the improved efficiency of N utilization in partially defaunated ruminants could be partly mediated by an increase in urea-N recycling.

Assessment of protozoa in Yunnan Yellow Cattle rumen based on the 18S rRNA sequences

Library of ruminal protozoal 18S rRNA of Yunnan Yellow Cattle has been constructed in the present study. Phylogenic analysis of sequences was meanwhile employed to reveal the diversity of protozoa in the rumen of Yunnan Yellow Cattle. One Yellow Cattle was fed malt meal (YCRPB) and the other was fed wheat straw (YCRPS). A protozoa-specific primer (P-SSU-342f) and a eukarya-specific primer (Medlin B) were used to amplify a 1,360-bp fragment of DNA encoding protozoal small subunit (SSU) ribosomal RNA from rumen fluid. The results showed as follows: A total of 121 clones were obtained and fell into four genera identified as Entodinium (66.9%), Dasytricha (5.8%), Isotricha (9.1%), and Diplodinium (18.2%). Within the genus Entidinium, 48 of the YCRPB sequences and 33 of the YCRPS sequences clustered with the Entodinium caudatum. 7 of the YCRPB sequences were phylogenetically placed within the genus Dasytricha. 11 of the YCRPB sequences were related with high confidence to Isotricha intestinalis. 22 of the YCRPS sequences were phylogenetically placed within the genus Diplodinium. The predominant protozoal genus identified in the rumen fluid belonged to the Entodinium group, and the divergences between two cattle may due to diet and individual differences.

Effect of a Yeast Culture on Nitrogen Balance and Digestion in Lambs Fed Early and Mature Orchard Grass

Hernández, R., González, S.S., Pinos-Rodríguez, J.M., Ortega, M.E., Hernández, A., Bueno, G. and Cobos, M. 2009. Effect of a yeast culture on nitrogen balance and digestion in lambs fed early and mature orchard grass. J. Appl. Anim. Res., 35: 53–56. To evaluate the effect of feeding a yeast culture (0 or 5 g/d per sheep) on digestion and N balance in lambs fed orchard grass hay cut at 5 or 16-wk of re-growth, 4 male Criollo lambs (45 ± 4 kg) fitted with ruminal cannulae in a 4x4 Latin square with a factorial 2x2 arrangement of treatments were used. Addition of a yeast culture did not affect (P>0.05) intake, rumen pH and ammonia N, N balance and total tract digestion of nutrients. Ruminal total protozoa changed only according to orchard grass maturity (P<0.05); however, treatments did not affect total and cellulolytic bacteria, rumen pH and rumen ammonia N concentration. It is concluded that addition of a yeast culture to lambs fed early and mature orchard grass did alter ruminal protozoa without affecting feed intake, total tract digestion and N balance.

Anticoccidial Versus Ruminal Defaunation Efficacy of Medium Chain Triglyceride Depending on Delivery Route in Calves

Since medium chain fatty acids (MCFAs) and their derivatives exert antimicrobial activities, their potential in controlling alimentary protozoa was examined in 12 calves infected with coccidia. Medium chain triglyceride (MCT), esterified fat of MCFAs, was administered into the rumen of 6 calves using an esophageal tube and into the abomasum of another 6 calves to ensure intestinal delivery by the function of the reticular groove reflex. Abomasal MCT inhibited the shedding of coccidial oocysts with less toxicity on ruminal protozoa. Conversely, intraruminal MCT showed negligible anticoccidial effect but toxicity on ruminal protozoa (defaunation). The anticoccidial efficacy was confirmed by abomasum feeding of MCT and not into the rumen. The results shed light on dietary fats for coccidial control.

Effects of live yeast cell supplementation to high concentrate diets on the toxicokinetics of ochratoxin A in sheep

Previous studies have indicated that high concentrate feeding reduces the ruminal degradation of the mycotoxin ochratoxin A (OA) to the less-toxic ochratoxin α (Oα) in ruminants. This is due to a pH-induced decrease in ruminal protozoa and subsequent increasing transfer of OA into the systemic circulation. The present study investigated whether stabilization of rumen pH by the live yeast cell supplementation to high concentrate diets affects the toxicokinetics of OA in sheep. Sheep were fed diets consisting of 70% concentrates and 30% grass silage (dry matter basis) supplemented without or with live yeast cells (Saccharomyces cerevisiae CNCM I-1077). After an adaptation period of 3 weeks, animals were given a single dose of OA (2.46 mg) in the form of contaminated wheat. Even though live yeast cells accelerated the recovery of ruminal pH from the decrease in pH induced by feeding, no effect on ruminal degradability and systemic availability of OA was recorded. Based on in vitro studies, live yeast cells and extracts of live yeast cell walls have been suggested as a mycotoxin-binding agent. However, supplementation with live yeast cells had no effect on the excretion pattern of OA in sheep, indicating that binding of OA to yeast components may be limited in ruminants. With respect to the toxicokinetics of OA, our results are in agreement with earlier results demonstrating that the hydrolysis of OA in the gastrointestinal tract of sheep is substantially less than previously described, especially if OA is ingested in combination with concentrate-rich diets. Our study demonstrates that feeding a live yeast cells product, registered as a feed additive for improving zootechnical performance, had no impact on the toxicokinetics of OA under the chosen conditions.