Validation of use of purine bases as a microbial marker by 15N labelling in growing lambs given high-concentrate diets: effects of grain processing, animal age and digesta sampling site (original) (raw)
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The origin of post-ruminal purine bases (PB) was studied in 24 growing lambs that were given a pelleted concentrate plus barley straw (C) or whole barley grain plus protein supplement (WB). Six lambs from each treatment were slaughtered at 10 and 30 days post weaning after 15 N labelling of microbial nitrogen (N) and PB. Microbial contribution to digesta nonammonia N (NAN) and PB was lower (P < 0•01) when estimated from duodenal rather than abomasal samples (0•36 v. 0•52 (s.e.d. 0•021) for NAN and 0•47 v. 0•77 (s.e.d. 0•029) for PB) as a result of endogenous contamination. In comparison with 15 N, total PB/N led to higher estimates (P < 0•01) of microbial contribution to abomasal NAN in WB treatment (0•62 v. 0•46 s.e.d. 0•049). The difference was removed after correcting for microbial PB, while this effect was not observed with < the C diet, resulting in a marker by diet interaction (P < 0•05). Abomasal PB flow increased (P < 0•1) from 10 to 30 days after weaning mainly due to the higher proportion of microbial PB (0•70 v. 0•81 (s.e.d. 0•047)). Rumen apparent PB degradation did not differ between diets in older lambs, but it was proportionally 0•39 lower for WB treatment (P < 0•05) in younger lambs. When the microbial PB flow was estimated indirectly from labelled microbial N and the PB/N ratio of bacterial extracts the estimates were in agreement with those derived from PB-15 N in the WB treatment but resulted in unrealistic values in lambs on diet C. Results suggest that significant proportions of dietary PB can escape rumen degradation which may lead to overestimation of microbial contribution to abomasal NAN when the PB/N ratio is used as marker. The extent of the overestimation is affected by the lamb age and grain processing.
British Journal of Nutrition, 1996
The present study compares estimates of rumen microbial-N production derived from duodenal flow measurements (15N and purine bases) with those from measurements of the urinary excretion of purine derivatives. Four Rasa Aragonesa ewes fitted with simple cannulas in the rumen and proximal duodenum were used. Four diets consisting of 550 g lucerne (Medicago sativa) hay/d as sole feed or supplemented with 220, 400 and 550 g rolled barley grain/d were given in a 4 x 4 random factorial arrangement. Duodenal digesta flows were determined by the dual-phase marker technique during continuous intraruminal infusions of Co-EDTA and Yb-acetate. Microbial contribution to the non-NH3N (NAN)flow was estimated from 15N enrichment and purines: N ratio in duodenal digesta and bacterial fractions isolated from the rumen content. Whole tract organic matter (OM) digestibility and duodenal flow of OM and NAN increased (P<0·001) with the level of barley supplementation. Digestible OM intake ranged from ...
Journal of animal science, 1991
Five sheep (average BW 62 kg) were fed 65% roughage: 35% concentrate diets (CP = 15%) in a 5 x 5 Latin square design to study the effects of combinations of defaunation and N supplements (soybean meal [SBM], corn gluten meal [CGM], blood meal [BM], urea, and casein) differing in ruminal degradation on ruminal microbial numbers and activity. Diets were fed twice daily (DM intake 1,759 g/d). Defaunation was accomplished with doses of 30 ml of alkanate 3SL3.sheep-1.d-1 for 3 d with 2 d of fasting. Treatment 1 (control) involved feeding faunated sheep a diet in which the supplemental N was 67% SBM N and 33% urea N. Treatment 2 involved feeding defaunated sheep the same diet as the control. Treatments 3, 4, and 5 involved feeding defaunated sheep diets in which the supplemental N source was either 67% CGM-BM N (CGM and BM combined on a 1:1 N ratio): 33% urea N, or 33% CGM-BM N:67% urea N or 33% CGM-BM N:33% urea N:33% casein N, respectively. Compared with the faunated control, defaunatio...
Journal of Animal Physiology and Animal Nutrition, 2010
This study examined the reticulo-rumen characteristics of the microbial community and its fermentative characteristics in milk-fed, at weaning and finished lambs in a conventional fattening system. Five lambs were assigned to each of three groups: milk-fed lambs slaughtered at 30 days (T30), weaned lambs slaughtered at 45 days (T45) and 'finished lambs' slaughtered at 90 days (T90). At slaughter, rumen size, fermentation parameters (pH, volatile fatty acids and microbial enzyme activity) and protozoal counts were recorded. Quantitative PCR was used to quantify the genes encoding 16S and 18S ribosomal DNA of the rumen bacterial and protozoal populations, respectively, and the sequential colonization of the rumen by cellulolytic (Ruminococcus albus, Ruminococcus flavefaciens) and amylolytic (Prevotella ruminicola, Streptococcus bovis) bacteria, and protozoa (Entodinium sp.). Denaturing gradient gel electrophoresis was used to study the development of rumen microbiota biodiversity. Intake of solid food before weaning caused a significant increase in rumen weight (p < 0.0001) and bacterial DNA (p < 0.05) and volatile fatty acid analysis concentration (p < 0.01), whereas pH declined. In milk-fed lambs, cellulolytic bacteria were evident after 30 days. Thereafter, in the 45-day and 90-day groups, the proportions of R. flavefaciens decreased and R. albus increased. Amylolytic bacteria were present in milk-fed lambs; the proportion of P. ruminicola increased in fattening lambs and S. bovis was the least abundant species. Protozoal concentrations were irregular; milk-fed lambs had a significant number of protozoa species from Entodinium and subfamily Isotrichiidae, but they disappeared at weaning. Lamb rumen were refaunated in some individuals at 90 days (Entodinium and subfamily Diplodiniinae spp.), although individual concentrations were variable.
Advances in Biological Sciences Research
This experiment aimed to compare the rumen microbial nitrogen supply in male and female Garut Sheep. Six male and female Garut sheep were put in the metabolism cages, fed ad libitum with Pennisetum purpureum and bran pollard with a ratio 60 : 40. This study begins with an adaptation period of 14 days. Urine collection was carried out for seven days. Urine samples be measured for purine derivatives (PD), consisting of allantoin, uric acid ,and xanthine-hypoxanthine. During the collection period, samples of feed, uneaten feed, and feces were taken out for dry matter and organic matter analysis. The total urinary PD excretions data were used to estimate microbial nitrogen supply (EMNS) based on the equation postulated with modification in endogenous PD excretion for male and female Garut sheeps. Data obtained were analyzed using the Independent Student T-Test design. The results showed that urinary PD excretion in male Garut sheep was higher than in females (0.160 vs 0.127 mmol/W 0.75 /day). EMNS in male Garut sheep also tended to be higher than in females (1.14 vs 0.74 g N/day). In conclusion, the excretion of PD and EMNS in male Garut sheep tended to be higher than in females.
Scientific Reports
The objective of this study was to determine the influence of a total-mixed ration including unsalable carrots at 45% DM on the rumen microbiome; and the plasma, rumen and liver metabolomes. Carrots discarded at processing were investigated as an energy-dense substitute for barley grain in a conventional feedlot diet, and improved feed conversion efficiency by 25%. Here, rumen fluid was collected from 34 Merino lambs at slaughter (n = 16 control; n = 18 carrot) after a feeding period of 11-weeks. The V4 region of the 16S rRNA gene was sequenced to profile archaeal and bacterial microbe communities. Further, a comprehensive, targeted profile of known metabolites was constructed for blood plasma, rumen fluid and biopsied liver metabolites using a gas chromatography mass spectrometry (GC–MS) metabolomics approach. An in vitro batch culture was used to characterise ruminal fermentation including gas and methane (CH4) production. In vivo rumen microbial community structure of carrot fed ...
ESTIMATION OF RUMEN MICROBIAL PROTEIN PRODUCTION AND RUMINAL PROTEIN DEGRADATION
Animal agricultural production systems are a major source of nitrogen (N) which may contribute to potential environmental pollution and one way to reduce losses of N to the environment is through feeding protein closer to requirements without overfeeding. This experiment was conducted toe valuate the effect of two rumen degraded protein (RDP) sources (non-protein N in the form of urea and amino acid-N in the form of casein) on microbial N (MN) flow, digestibility and production in lactating dairy cows. Eight ruminally and duodenally cannulated Holstein cows were fed one of four dietary treatments in a repeated 4x4 Latin square. The first diet (BASE) served as the negative control and contained 12.2% crude protein (CP). The remaining diets contained either urea (UREA), casein (CAS), or a combination of both (U+C) on an equal N basis and contained 15.0% CP. Cows were infused with Co-EDTA, Cr-mordanted NDF and 15N which were used as markers for liquid, solid and bacteria flow, respectively. Intake, duodenal MN flow, milk production, and digestibility were lower when cows were fed the BASE diet and there were differences in MN flow between the UREA, CAS or U+C diets. Ruminal starch digestibility was highest when cows were fed the U+C diet and NDF digestibility was higher when cows were fed the CAS and U+C diets. Therefore a source of RDP with amino acids was required to maximize both fiber and starch digestibility. In the same study flow rates of various particle sizes from reticulum and duodenal samples were compared as well as the bacterial attachment to these particles as they flow through the digestive tract. Digesta collected from both the reticulum and the duodenum were poured over a set of sieves to allow for particle size separation. Flow rates of DM, NDF and N differed depending on particle size and the composition of the various sieve fractions differed but was still similar between reticulum and duodenal samples. Bacterial attachment differed depending on particle size and location in the digestive tract. These results indicate the importance of particle size passage from the rumen and the usefulness of flow markers to adjust for unrepresentative sampling from both the rumen and the duodenum. A better understanding of the responses of MN flow due to RDP source can lead to improved diet formulation models which can be used to balance dairy cattle rations for optimum production yet minimize losses of N from the cow and therefore to the environment.
Journal of Animal Science, 2009
Six ruminally and duodenally cannulated sheep were used in a partially replicated 4 × 4 Latin square to evaluate the effects of 4 diets on microbial synthesis, microbial populations, and ruminal digestion. The experimental diets had forage to concentrate ratios (F:C; DM basis) of 70:30 (HF) or 30:70 (HC) with alfalfa hay (A) or grass hay (G) as forage and were designated as HFA, HCA, HFG, and HCG. The concentrate was based on barley, gluten feed, wheat middlings, soybean meal, palmkern meal, wheat, corn, and mineral-vitamin premix in the proportions of 22, 20, 20, 13, 12, 5, 5, and 3%, respectively (as-is basis). Sheep were fed the diets at a daily rate of 56 g/kg of BW 0.75 to minimize feed selection. High-concentrate diets resulted in greater (P < 0.001) total tract apparent OM digestibility compared with HF diets, but no differences were detected in NDF digestibility. Ruminal digestibility of OM, NDF, and ADF was decreased by increasing the proportion of concentrate, but no differences between forages were detected. Compared with sheep fed HF diets, sheep receiving HC diets had less ruminal pH values and acetate proportions, but greater butyrate proportions. No differences among diets were detected in numbers of cellulolytic bacteria, but protozoa numbers were less (P = 0.004) and total bacteria numbers tended (P = 0.08) to be less for HC diets. Carboxymethylcellulase, xylanase, and amylase activities were greater for HC compared with HF diets, with A diets showing greater (P = 0.008) carboxymethylcellulase activities than G diets. Retained N ranged from 28.7 to 37.9% of N intake and was not affected by F:C (P = 0.62) or the type of forage (P = 0.31). Microbial N synthesis and its efficiency was greater (P < 0.001) for HC diets compared with HF diets. The results indicate that concentrates with low cereal content can be included in the diet of sheep up to 70% of the diet without detrimental effects on ruminal activity, microbial synthesis efficiency, and N losses.
Journal of Animal Science, 2009
Six ruminally and duodenally cannulated sheep were used in a partially replicated 4 × 4 Latin square to evaluate the effects of 4 diets on microbial synthesis, microbial populations, and ruminal digestion. The experimental diets had forage to concentrate ratios (F:C; DM basis) of 70:30 (HF) or 30:70 (HC) with alfalfa hay (A) or grass hay (G) as forage and were designated as HFA, HCA, HFG, and HCG. The concentrate was based on barley, gluten feed, wheat middlings, soybean meal, palmkern meal, wheat, corn, and mineral-vitamin premix in the proportions of 22, 20, 20, 13, 12, 5, 5, and 3%, respectively (as-is basis). Sheep were fed the diets at a daily rate of 56 g/kg of BW 0.75 to minimize feed selection. High-concentrate diets resulted in greater (P < 0.001) total tract apparent OM digestibility compared with HF diets, but no differences were detected in NDF digestibility. Ruminal digestibility of OM, NDF, and ADF was decreased by increasing the proportion of concentrate, but no differences between forages were detected. Compared with sheep fed HF diets, sheep receiving HC diets had less ruminal pH values and acetate proportions, but greater butyrate proportions. No differences among diets were detected in numbers of cellulolytic bacteria, but protozoa numbers were less (P = 0.004) and total bacteria numbers tended (P = 0.08) to be less for HC diets. Carboxymethylcellulase, xylanase, and amylase activities were greater for HC compared with HF diets, with A diets showing greater (P = 0.008) carboxymethylcellulase activities than G diets. Retained N ranged from 28.7 to 37.9% of N intake and was not affected by F:C (P = 0.62) or the type of forage (P = 0.31). Microbial N synthesis and its efficiency was greater (P < 0.001) for HC diets compared with HF diets. The results indicate that concentrates with low cereal content can be included in the diet of sheep up to 70% of the diet without detrimental effects on ruminal activity, microbial synthesis efficiency, and N losses.
Animal, 2011
Previous studies have indicated that15N enrichment of solid-associated bacteria (SAB) may be predicted from the same value in liquid-associated bacteria (LAB). The aims of this study were to confirm this and to measure the error in the nutrient supply from SAB, when LAB are used as the reference sample. For this purpose, the chemical and amino acid (AA) compositions of both the bacterial populations were studied in four experiments carried out on different groups of three rumen cannulated wethers. Diets (one in Experiments 1 and 4 and three in Experiments 2 and 3) had forage-to-concentrate ratios (dry matter (DM) basis) between 2 : 1 and 40 : 60, and were consumed at intake levels between 40 and 75 g DM/kg (BW)0.75. The bacteria samples were isolated after continuous infusion of (15NH4)2SO4(40, 18, 30 and 25 mg15N/day, in Experiments 1 to 4, respectively) for at least 14 days. In all experiments, SAB had consistently higher concentrations of organic matter (826v.716 g/kg DM, as aver...