Excretion Of Purine Derivatives Research Articles

Parâmetros da fermentação ruminal e concentração de derivados de purina de vacas em lactação alimentadas com castanha de caju

Avaliaram-se os parâmetros de fermentação ruminal e a concentração de derivados de purinas na urina de vacas leiteiras alimentadas com teores crescentes de castanha de caju na dieta. Foram utilizadas oito vacas Holandesas multíparas, sendo quatro fistuladas no rúmen, com produção média de 28±4kg de leite/dia. O delineamento experimental adotado foi o quadrado latino 4x4, com parcelas subdivididas para os parâmetros ruminais e duplo para determinação dos derivados de purina. Os tratamentos avaliados consistiram na inclusão de 0; 8; 16 e 24% de castanha de caju moída na porção concentrada da dieta. O comportamento do pH ruminal foi semelhante entre as dietas avaliadas segundo os tempos após alimentação. A concentração média de nitrogênio amoniacal foi 12,70mg/100mL de líquido ruminal. Os valores médios de acetato e butirato apresentaram padrão linear de resposta, contudo a relação acetato:propionato não foi alterada pela adição do coproduto. As excreções de derivados de purina na urina não variaram significativamente (P>0,05) com a adição de castanha de caju. A inclusão de castanha de caju não afetou os parâmetros de fermentação ruminal nem as concentrações de derivados de purinas; dessa forma, pode ser recomendada como alternativa potencial na alimentação de vacas leiteiras em lactação.

Effect of High-Dose Nano-selenium and Selenium–Yeast on Feed Digestibility, Rumen Fermentation, and Purine Derivatives in Sheep

The aim of this study was to evaluate the effect of nano-selenium (NS) and yeast-selenium (YS) supplementation on feed digestibility, rumen fermentation, and urinary purine derivatives in sheep. Six male ruminally cannulated sheep, average 43.32 ± 4.8kg of BW, were used in a replicated 3 × 3 Latin square experiment. The treatments were control (without NS and YS), NS with 4g nano-Se (provide 4mg Se), and YS with 4g Se-yeast (provide 4mg Se) per kilogram of diet dry matter (DM), respectively. Experimental periods were 25days with 15days of adaptation and 10days of sampling. Ruminal pH, ammonia N concentration, molar proportion of propionate, and ratio of acetate to propionate were decreased (P < 0.01), and total ruminal VFA concentration was increased with NS and YS supplementation (P < 0.01). In situ ruminal neutral detergent fiber (aNDF) degradation of Leymus chinensis (P < 0.01) and crude protein (CP) of soybean meal (P < 0.01) were significantly improved by Se supplementation. Digestibilities of DM, organic matter, crude protein, ether extract, aNDF, and ADF in the total tract and urinary excretion of purine derivatives were also affected by feeding Se supplementation diets (P < 0.01). Ruminal fermentation was improved by feeding NS, and feed conversion efficiency was also increased compared with YS (P < 0.01). We concluded that nano-Se can be used as a preferentially available selenium source in ruminant nutrition.

Urinary excretion of purine derivatives, microbial protein synthesis, nitrogen use, and ruminal fermentation in sheep and goats fed diets of different quality1

The objective of this study was to compare N balance, microbial N flow (MNF) estimated from purine derivatives (PD) urinary excretion, and its variation when estimated using purine bases:N ratios in liquid associated bacteria (LAB) from models reported in the literature (MNF - response models) or measured ratios in liquid and solid-associated bacterial (SAB) pellets (MNF-LAB+SAB), diet digestibility, and rumen fermentation variables in sheep and goats fed 3 different practical, quality diets to study interspecies differences concerning N use as accurately as possible. Four mature female Merino sheep and 4 mature female Granadina goats, each fitted with a ruminal cannula, were used in 3 × 3 Latin square design with an extra animal. Two experimental diets had a forage-to-concentrate ratio of 70:30 (DM basis) with alfalfa hay (ALC) or grass hay (GRC) as forage, and the third diet contained 70% concentrate and 30% alfalfa hay (CAL). All animals were fed the diets at a daily rate of 56 g/kg BW(0.75) to minimize feed selection. Digestibility of nutrients was similar (P = 0.16 to 0.88) in the 2 species, but some animal species × diet interactions (P = 0.01 to 0.04) were detected. There were small differences between the fermentation patterns of both animal species. Goats showed decreased VFA concentrations (P = 0.005) and butyrate proportions (P = 0.04), and greater acetate proportions (P = 0.02) compared with sheep, whereas N intake and percentage of N intake excreted in feces were similar in both species (P = 0.58 and 0.15, respectively), the percentage excreted via the urine was greater in goats compared with sheep (P < 0.001). As a consequence, sheep had greater (P < 0.001) N retention than goats (averaged across diets, 32.6% and 16.1% of N intake, respectively). There were no differences (P = 0.95) between animal species in total PD excretion, but goats showed a greater excretion of allantoin (P = 0.01) and decreased excretion of xanthine (P = 0.008) and hypoxanthine (P = 0.007) compared with sheep. In general, differences between sheep and goats were more pronounced for the medium-quality diet (GRC) compared with those of high-quality diet (ALC and CAL). The greater urinary losses in goats would indicate a greater contribution of goats to N environmental contamination compared with sheep.

Influences of dietary nitrogen and non-fiber carbohydrate levels on apparent digestibility, rumen fermentation and nitrogen utilization in growing yaks fed low quality forage based-diet

The effects of dietary N and non-fiber carbohydrate (NFC) levels on nutrient digestibility, ruminal fermentation, and nitrogen utilization were investigated in growing yaks. Four diets (N content: 1.43%, 1.97%, 2.45% and 2.90% of DM basis; ratio of dietary NFC and RDP: 5.9, 3.2, 2.2 and 1.6) were offered to four yaks in a 4×4 Latin square design. Dietary N and NFC did not affect the gastrointestinal tract digestibility of DM, organic matter (OM), NFC, NDF, or ADF (P>0.05). Ruminal pH value, molar proportion of butyrate, and ratio of acetate to propionate were not affected by the diets (P>0.05); whereas, molar proportions of acetate, propionate, iso-butyrate, iso-valerate, valerate, and total VFA concentration in rumen fluid increased linearly (P<0.01) with increase in dietary N and decrease in dietary NFC. Except for ruminal NH3-N and soluble protein N, free amino acid-N and peptide-N maintained constantly within the sampling time (from 0 to 8h of post feeding; P>0.05). The increment of N intake linearly increased the N retention (P=0.003), but no difference (P>0.05) was observed in the ratio of N retention to the gastrointestinal trace absorbed N after dietary N reached to 2.45% of DM. Microbial N supply had linear and quadric (P<0.001) responses to the dietary N, and the highest microbial N synthesis efficiency was observed when the yaks were fed with 1.97% N diet in which ratio of NFC to RDP was 3.2, and dietary NFC and RDP were 20.2% and 6.7% of DM, respectively. Total purine derivatives excretion and microbial purine N:total N had a quadric (P<0.05) response to the dietary N. Results of the current experiment suggest that maximizing N utilization and microbial efficiency were obtained when the yaks were fed a diet with an optimal dietary ratio of NFC to RDP.

Modelling urinary purine derivatives excretion as a tool to estimate microbial rumen outflow in alpacas (Vicugna pacos)

Three experiments were carried out to establish a model to estimate the forestomach microbial yield based on the urinary excretion of purine derivatives (PD: allantoin, uric acid, xanthine and hypoxantine) in alpacas (Vicugna pacos). In Experiment 1, endogenous PD excretion was measured in two fasted adult male alpacas for seven consecutive days. Daily urinary PD excretion (μmol/kg BW0.75) decreased during fasting to a minimum value of 194.8 (s.e. 18.4), ranging from 215.3 to 174.3. In Experiment 2, the relationship between purine bases (PB) input and urinary PD output was defined in two alpacas fitted with an infusion catheter at the terminal third compartment of the forestomach (C3). Animals were fed alfalfa hay at a maintenance level, and four RNA-doses (4.2, 8.3, 12.5 and 16.6mmol PB/day; RNA from Torula yeast) were continuously infused at random into the C3 in four successive 120 h-periods. Urinary recovery of C3 infused purines averaged 0.615 (s.e. 0.0006)mmol/day. In Experiment 3, urinary PD response to levels of feed intake corresponding to 100, 75, 50 and 20% of the previous voluntary intake was evaluated. The amount of PD excretion in urine increased linearly (r=0.867) with digestible organic matter intake (DOMI), and the slope of the regression (16.7mmol PD/kg DOMI) can be assumed as an index of microbial yield.

Effects of 2-methylbutyrate on rumen fermentation, ruminal enzyme activities, urinary excretion of purine derivatives and feed digestibility in steers

The objective of this study was to evaluate the effects of 2-methylbutyrate (2MB) supplementation on rumen fermentation, ruminal enzyme activities, urinary excretion of purine derivatives and feed digestibility in the total tract of steers. Eight ruminally cannulated Simmental steers were used in a replicated 4×4 Latin square experiment. The treatments were: control (without 2MB), L2MB, M2MB and H2MB with 8.4, 16.8 and 25.2g 2MB per steer per day, respectively. 2-methylbutyrate was hand-mixed into the concentrate portion. Diet consisted of 60% corn stover and 40% concentrate (dry matter [DM] basis). Dry matter intake (averaged 9kg/d) was restricted to a maximum of 90% of ad libitum intake. Ruminal pH was linearly decreased, whereas total VFA concentration (range of 64.19–71.06mM) was linearly (p<0.01) and quadratically (p<0.01) increased with increasing 2MB supplementation. Ratio of acetate to propionate increased linearly (p<0.01) from 2.53 to 3.80 as 2MB supplementation increased due to the increased in acetate production and decreased in propionate production. Activities of CMCase and xylanase were linearly increased, whereas that of protease was linearly reduced with increasing 2-methylbutyric supplementation. In situ ruminal NDF degradation of corn stover was improved but the CP degradability of soybean meal was decreased with increasing 2MB supplementation. Urinary excretion of purine derivatives was quadratically (p<0.01) changed with altering 2MB supplementation (52.74, 58.50, 59.17 and 54.36mmol/d for control, low, medium and high 2MB supplementation, respectively). Similarly, digestibilities of DM, NDF and CP in the total tract were also linearly and quadratically increased with increasing 2MB supplementation. The present results indicate that supplementation of diet with 2MB improved rumen fermentation and feed digestion in beef cattle. It was suggested that the 2MB stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum 2MB dose was about 16.8g 2MB per steer per day.

Effects of pistachio by-product in replacement of lucerne hay on microbial protein synthesis and fermentative parameters in the rumen of sheep

This study was conducted to evaluate the effect of partial and total substitution of lucerne hay with pistachio by-product on nutrient intake, apparent digestibility, rumen fermentation, digesta kinetics, blood metabolites, nitrogen retention and microbial protein synthesis in Baloochi sheep. Six sheep with a bodyweight of 40.1 ± 1.77 kg fitted with ruminal and abomasal cannulae were assigned at random to three diets in a double 3 × 3 Latin-square design. The dietary treatments included a control (basal diet), low pistachio by-product diet (50% of the lucerne hay in the basal diet was replaced by pistachio by-product), and high pistachio by-product diet (all of the lucerne hay in the basal diet was replaced by pistachio by-product). The daily basal diet was 500 g/kg DM lucerne hay, 250 g/kg DM wheat straw, 210 g/kg DM barley grain, 30 g/kg DM cotton seed meal, 8 g/kg DM vitamin–mineral supplement and 2 g/kg DM salt. Faeces and urine were collected for 8 days and used to estimate digestibility, nitrogen retention and microbial protein synthesis. Sheep were dosed ruminally with Cr-EDTA (2.27 g/L) and rumen samples were evaluated for pH, volatile fatty acids, ammonia nitrogen concentrations and digesta kinetics. The intake of neutral detergent fibre, purine derivatives excretion, volatile fatty acid concentrations in the rumen and ammonia nitrogen in the abomasum decreased (P &lt; 0.05). Ether extract intake and ruminal pH was increased at 5 h after feeding (P &lt; 0.05) as the level of pistachio by-product in the diet increased. Total pistachio by-product replacement for lucerne hay increased (P &lt; 0.05) apparent digestibility of nitrogen, ether extract, organic matter and nitrogen retention and decreased (P &lt; 0.05) microbial protein synthesis, efficiency of microbial protein synthesis and ammonia nitrogen in the rumen. The inclusion of pistachio by-product had no effect on blood metabolites and digesta kinetics. Based on these results it was concluded that pistachio by-product can be considered as a useful replacement for lucerne hay in the diet of Baloochi sheep without any negative impacts on their responses. Moreover, pistachio by-product inclusion in diet improved nitrogen metabolism in Baloochi sheep.

A comparative study on mimosine, 3,4-dihydroxy pyridone (3,4-DHP) and 2,3-dihydroxy pyridone (2,3-DHP), purine derivatives (PD) excretion in the urine, thyroid hormone and blood metabolites profiles of Thai swamp buffalo (Bubalus bubalis) and Murrah buffalo (Bubalus bubalis)

Four Thai swamp buffaloes (SB) and four Murrah buffaloes (MB) fed a based diet of fresh ruzi grass (Bachiaria ruziziensis) with an increased proportion of fresh leucaena leaves. Intake of nutrients in animals increased when ruzi grass was mixed with leucaena. Digestibility of nutrients were the highest in SB and MB fed diets containing 25% and 50% of leucaena, respectively, and nitrogen (N) balances in both animal breeds were varied among diets. The regression equation coefficient of mimosine + DHP in the urine was twice as high in SB than in MB. Urinary purine derivatives excretion rate in SB was higher than that in MB. Plasma triiodothyronine and thyroxine declined in both animal breeds fed a diet containing >1 g mimosine intake/kg BW(0.75)/day. Plasma urea-N was the lowest in SB, but the highest in MB when fed a diet containing 84% of leucaena. Plasma β-HBA in SB have declined when diets contained >50% of leucaena but that in MB was not affected by any diet. In conclusion, the effect of leucaena in diet upon buffalo breeds depends on the proportion of leucaena in the diet, mimosine contents and condensed tannins components.

Effect of different rumen degradable nitrogen levels on microbial protein synthesis and digestibility in sheep fed on finger millet straw (Eleucine coracana) based diet

Studies were conducted to determine adequate rumen degradable nitrogen (RDN) levels for optimum microbial protein synthesis and digestibility of nutrients in adult Bandur sheep fed on finger millet straw (FMS) based diet. Thirty Bandur sheep were divided into five groups of six animals each using a balanced completely randomized design. Animals in all groups were fed FMS as a basal roughage and solvent-extracted soybean meal (SBM) as a nitrogen source. The sheep in group 1 (G1) were offered FMS for ad libitum intake. Animals in group 2, 3, 4 and 5 (G2, G3, G4 and G5) were supplemented with SBM to provide RDN level of 16.2, 20.7, 24.7 and 26.6g/kg digestible organic matter intake (DOMI) or 24.9, 31.8, 38.1 and 41.0g/kg digestible organic matter apparently digested in the rumen (DOMR) respectively, along with FMS. The daily total dry matter (DM) and organic matter (OM) intakes showed a linear increase (P<0.05) with increasing levels of RDN supplementation. Digestibility coefficients of DM, OM (linear: P<0.01), crude protein (CP), ether extract (EE) (quadratic: P<0.001), neutral detergent fiber (NDF) and acid detergent fiber (ADF) (quadratic: P<0.05) increased as the level of RDN supplementation increased from G1 to G5. The values for total purine derivatives (TPD) excretion (mmol/day and mmol/kgW0.75) (quadratic: P<0.05), the levels of microbial purine absorption and microbial nitrogen supply (MNSg/day, g/kgDOMI and g/kgDOMR) (quadratic: P<0.01) increased, while microbial nitrogen to total urinary nitrogen ratio (MN:UN) decreased (linear: P<0.01) with the increased RDN level, indicating the efficient conversion of RDN into microbial protein synthesis for G2 animals among the RDN supplemented groups. This study indicated that 16gRDN/kgDOMI or 25gRDN/kgDOMR may be adequate for optimum microbial protein synthesis and digestibility of nutrients, thereby improving plane of nutrition in sheep fed on finger millet straw based diet. The additional RDN supplied beyond certain limit (above 16gRDN/kgDOMI or 25gRDN/kgDOMR) may not be beneficial for improving the digestibility of diet especially on straw based diets.

Effects of feeding different levels of dietary fiber through the addition of corn stover on nutrient utilization of dairy heifers precision-fed high and low concentrate diets

The objective of this experiment was to assess the effects of manipulating dietary fiber by replacing corn silage (CS) with lower quality forage as corn stover (CST) when used in high concentrate (HC) and low concentrate (LC) diets for precision-fed dairy heifers. Eight Holstein heifers (335.6±7.41kg of body weight) were randomly assigned to 2 levels of concentrate: HC (20% forage) and LC (80% forage), and to a forage type sequence [0% of forage as corn stover (CST), 100% corn silage (CS); 20% CST, 80% CS; 40% CST, 60% CS; and 60% CST, 40% CS] within concentrate level administered according to a split-plot, 4×4 Latin square design (21-d periods). Heifers fed HC had higher apparent total-tract dry matter digestibility (DMD). Increasing the fiber level by increasing the amount of CST in the diet resulted in a linear decrease of DMD and organic matter digestibility. Heifers fed LC diets had higher neutral detergent fiber (NDF) digestibility and tended to have lower acid detergent fiber (ADF) digestibility than those fed HC diets. Substituting CS with 20% CST resulted in the highest NDF and ADF digestibilities. Digestibility of N was not different, but N retention increased for HC and decreased quadratically for LC diets. Heifers fed HC diets decreased fecal output, and CST linearly increased these parameters. Urine volume tended to be higher for HC-fed heifers, and increasing dietary fiber through CST inclusion tended to decrease urine output. This shift in water excretion resulted in similar total manure output. Total purine derivative excretion did not differ between treatments, but interacted with CST addition, resulting in a linear increase in microbial protein flow to the duodenum in HC-fed heifers and in a linear decrease in LC diets as CST increased. In conclusion, increasing dietary fiber through CST decreased DMD and organic matter digestibility linearly, whereas NDF and ADF digestibility were maximized when 20% CST was added to HC and LC diets. Microbial protein synthesis increased and decreased linearly with CST addition in HC and LC diets, respectively. Retention of N increased and decreased quadratically with CST addition in HC and LC diets, respectively. Total manure excretion was not different between HC or LC diets.

Productive performance, nutrient digestion and metabolism of Holstein (Bos taurus) and Nellore (Bos taurus indicus) cattle and Mediterranean Buffaloes (Bubalis bubalis) fed with corn-silage based diets

The objective of this study was to evaluate the productive performance, nutrients digestion and metabolism of three different genetic groups fed with the same diet based on corn silage. 30 heifers in growth were used of three groups of cattle, the following: Nellore (Bos taurus indicus) (n=10), Holstein (Bos taurus taurus) (n=10), and Mediterranean buffaloes (Bubalis bubalis) (n=10). The animals were fed in groups and received the same experimental diet composed of corn silage and concentrate for growing heifers. In the evaluation of animals the performance, consumption and total apparent digestibility of dry matter and nutrients with the aid of internal markers (chromic oxide) and external (iADF), rumen fermentation, excretion of purine derivatives, nitrogen balance and blood metabolites were measured.No differences were observed in animal performance. There were differences in nutrient intake and apparent digestibility of dry matter and nutrients in different groups of cattle. The concentration of ammonia nitrogen (NH3-N) and short chain fatty acids (SCFA) in the rumen were higher and lower, respectively, for the group of buffaloes in relation to other experimental groups evaluated. When considering the excretion of total purine derivatives, buffaloes showed the lowest value compared to other genetic groups evaluated; about 61.76% of the total genetic group Nellore and 57.62% of the total genetic group Holstein with an average of 33.67mmol/day. For the buffaloes, the excretion of xanthine and hypoxanthine observed was of 5.11% of total purine derivatives. There was a better nitrogen balance (g/day) for groups of Holstein heifers and Nellore in relation to the group of buffalo heifers. There were differences in the concentrations of urea and urea nitrogen in serum and liver enzymes where the buffaloes had higher values in relation at the bovines. There is a great metabolic diversity among the experimental groups evaluated and it was more exacerbated among buffaloes and bovines, when submitted to the same diet and same management conditions.

Metabolism of microbial nitrogen in ruminants with special reference to nucleic acids

Characteristically the metabolism of microbial nitrogen (N) compounds in ruminants involves the degradation of dietary N and synthesis of microbial protein (MP), compounds including a small amount of peptides and free amino acids, which may account for 75-85% of total N and the remainder are nucleic acids (NA: DNA and RNA). Generally rumen microbes contain 10-25% NA-N of the total N while 70-80% is in the form of RNA. This paper describes the degradation and synthesis of NA in the rumen and their fate in the lower digestive tracts. Their physiological and nutritional significance in different types of ruminant animals is also discussed. The research works on NA metabolism in ruminants has been mainly on metabolism of purines after rumen microbial digestion and absorption in the lower gut. Subsequently, the fate of absorbed purines has been intensively investigated to assess the extent of MP synthesis in the rumen. The method for predicting ruminal synthesized MP and subsequently digested MP has been proposed using urinary purine derivative (PD) excretion in sheep and cattle fed on ordinary feed. The latter approach has now been adopted for calculation of protein supply in some feeding standards, although there are still difficulties in predicting representative samples of rumen microbes, and also uncertainties in variations of non-renal and endogenous purine losses.

Nitrogen partitioning and isotopic fractionation in dairy cows consuming diets based on a range of contrasting forages

Nine multiparous Holstein-Friesian cows (initially 97 d in milk), were used in a 3×3 lattice square design experiment with 4-wk periods. All cows received 4kg/d concentrates and dietary treatments were based on silages offered ad libitum: perennial ryegrass (PRG); timothy (TIM); tall fescue (TF); red clover (RC); red clover/corn silage mixture [40/60 on a dry matter (DM) basis; RCC]; red clover/whole-crop oat silage mixture (40/60 on a DM basis; RCO); or red clover/whole-crop oat silage mixture (25/75 on a DM basis; ORC). The remaining treatments were based on RCO with feed intake restricted to the level of PRG (RCOr) or with a low protein concentrate (50/50 mixture of barley and molassed sugar beet pulp; RCOlp). Experiment objectives were to evaluate diet effects on N partitioning and N isotopic fractionation. Yields of milk and milk protein were consistently high for diets RC, RCC, and RCO and low for the diets based on poorly ensiled grass silages. Restriction of intake (RCOr) and inclusion of a higher proportion of whole-crop oat silage (ORC) and the low-protein concentrate (RCOlp) led to some loss of production. Diet had little effect on milk fat, protein, and lactose concentrations: low concentrations of milk protein and lactose reflect the restricted energy intakes for all treatments. The highest diet digestibilities were measured for RC and PRG, whereas increasing inclusion of the whole-crop oat silage (0, 60, and 75% of forage DM) led to a marked decrease in diet digestibility (0.717, 0.624, and 0.574g/g, respectively). Urinary excretion of purine derivatives, an indicator for rumen microbial protein synthesis, was significantly higher for RCC than for TIM and TF. Nitrogen intake ranged between 359 and 626g/d (treatment means). Partitioning of N intake to feces and urine was closely related to N intake, although urinary N losses were less than predicted from N intake for the 60/40 mixtures of cereal silage and red clover silage. The 15N content of milk, urine, and feces were all influenced by diet 15N content. Isotopic fractionation meant that feces and milk were enriched and urine was depleted in 15N relative to the diet. Significant relationships were observed between the extent of enrichment of urine, feces, and milk, suggesting some commonality in fractionation pathways. The trend for the lowest 15N enrichment in milk protein occurring in diets with low N-use efficiency (milk N/feed N) was contrary to expectations, possibly because of endogenous contributions to milk protein or fractionation when dietary ammonia was incorporated into microbial protein.

Consumo, digestibilidade total, produção de proteína microbiana e balanço de nitrogênio em dietas para ruminantes de subprodutos

Avaliaram-se os efeitos da inclusão da fonte - subproduto do cacau, mandioca-casca, mandioca-caule e farelo de glúten de milho - e da proporção - 10 e 30% - de subprodutos, em substituição parcial à silagem de milho sobre consumo, digestibilidade dos nutrientes, produção de proteína microbiana, balanço de nitrogênio, predição das frações digestíveis e nutrientes digestíveis totais. Os consumos de matéria seca e de fibra em detergente neutro foram influenciados pela fonte de subproduto. A fonte de subproduto influiu na digestibilidade do extrato etéreo e dos carboidratos não fibrosos. O subproduto farelo de glúten de milho apresentou valor energético 17% maior do que a da silagem de milho, enquanto os da mandioca-casca, da mandioca-caule e do cacau apresentaram valores energéticos 10, 19 e 38% menores do que o valor observado para silagem de milho. A fonte e o nível de subproduto não influíram na excreção urinária de derivados de purinas totais, de purinas absorvidas e de nitrogênio microbiano, e na eficiência microbiana. A fonte do subproduto influenciou a ingestão, a excreção nas fezes e na urina dos compostos nitrogenados e o balanço de nitrogênio. O farelo de glúten de milho e a mandioca-casca podem substituir, parcialmente, os concentrados energéticos, sem prejuízos para consumo, digestibilidade, eficiência microbiana e retenção de nitrogênio

Rumen degradable nitrogen requirements for optimum microbial protein synthesis and nutrient utilization in sheep fed on finger millet straw (Eleucine coracana) based diet

Studies were conducted to determine the rumen degradable nitrogen (RDN) requirement levels for optimum microbial protein synthesis and nutrient utilization in Nellore rams fed on finger millet straw (FMS) based diet. Thirty six Nellore sheep were randomly divided into four groups of nine animals each using the balanced completely randomized design. Animals in all the groups were fed finger millet straw as a basal roughage and groundnut cake (GNC) was offered daily in two equal halves in the morning (8.00AM) and evening (4.00PM) as RDN source. The animals in group I (GI) were fed with ad libitum FMS. Animals in group II, III and IV (GII, GIII, and IV) were offered GNC @ 12.4, 16.6, and 21.1g RDN/kg digestible organic matter (DOM) along with FMS. The daily total dry matter (DM) and organic matter (OM) intakes linearly increased (P<0.05) with increasing level of RDN supplementation while there was no difference in total DM and OM intake/kg W0.75 among different experimental groups. The digestibility coefficients of DM (P<0.001), OM (P<0.001), crude protein (CP) (P<0.001), ether extract (EE) (P<0.001), neutral detergent fibre (NDF) (P<0.01) and acid detergent fibre (ADF) (P<0.03) increased quadratically with increasing level of RDN supplementation from GI to GIV. The purine derivatives (PD) excretion, microbial purine absorption and microbial nitrogen supply (MNSg/day) linearly increased (P<0.001) as the level of RDN supplementation increased. There was no difference in nitrogen capture efficiency (NCE) and microbial nitrogen to total urinary nitrogen ratio (MN:UN) among the RDN supplemented groups. This study indicated that 12g RDN/kg digestible organic matter intake (RDNg/kg DOMI) or 18g RDN/kg OM apparently digested in the rumen (RDNg/kg DOMR) may be adequate for optimum microbial protein synthesis and digestibility of nutrients, there by improved plane of nutrition in sheep fed on finger millet straw based diet.

Effect of elemental nano-selenium on feed digestibility, rumen fermentation, and purine derivatives in sheep

The objective of this experiment was to study the effect of elemental nano-selenium (NS) on feed digestibility, rumen fermentation, and urinary purine derivatives in sheep. Eight male ruminally cannulated sheep (42.5±3.2kg of body weight, BW) were used in a replicated 4×4 Latin square experiment in four 20 day periods. Depending on treatment designation, sheep were fed the basal diet supplemented with 0 (control), 0.3, 3 and 6g of nano-Se/kg dry matter (DM). Ruminal pH (range of 6.68–6.80) and ammonia N concentration (range of 9.95–12.49mg/100mL) was decreased (P<0.01), and total VFA concentration (range of 73.63–77.72mM) was increased linearly (P<0.01) and quadratically (P<0.01) with increasing nano-Se supplementation. The ratio of acetate to propionate was linearly (P<0.01) and quadratically (P<0.01) decreased due to the increasing of propionate concentration. In situ ruminal neutral detergent fiber (aNDF) degradation of Leymus chinensis and crude protein (CP) of soybean meal were linearly (P<0.01) and quadratically (P<0.01) improved by feeding nano-Se. Similarly, nutrients digestibility in the total tract and urinary excretion of purine derivatives were also quadratically (P<0.01) changed by increasing nano-Se supplementation. The present results indicated that nano-Se supplementation in basal diet improved rumen fermentation and feed utilization. Nano-Se could also stimulate rumen microbial activity, digestive microorganisms or enzyme activity. The optimum dose of nano-Se was about 3.0g/kg dietary DM in sheep.

Endogenous fraction and urinary recovery of purine derivatives obtained by different methods in Nellore cattle1

Two experiments were conducted to assess the endogenous fraction of purine derivative (PD) excretion, urinary recovery, and intestinal digestibility of purines in Nellore heifers. For both experiments, 8 Nellore heifers fitted with ruminal and abomasal cannulas were allocated to two 4 × 4 Latin squares. The diets were based on corn silage and concentrate (60 and 40% DM basis, respectively); feces and urine samples were obtained by total collection, and abomasal DM flow was estimated using indigestible NDF as an internal marker. In Exp. I, 4 of the 8 heifers (BW 258 ± 20 kg) were also fitted with ileal cannula. The planned treatments were 4 different DMI: 1.2, 1.6, 2.0, and 2.4% of BW (DM basis). The endogenous losses and purine recovery as urinary PD were estimated using linear regression between daily urinary PD excretion (Y) and daily abomasal flow of purine bases (X), expressed in millimoles per kilogram of BW(0.75). In Exp. II, the same 8 Nellore heifers (BW of 296 ± 15 kg) were fed at 1.37% BW (DM basis). The treatments were the infusion of purines (RNA from torula yeast, type VI, Sigma) into the abomasum in increasing amounts (0, 33, 66, and 100 mmol/d). All statistical analyses were performed using the PROC MIXED procedure in SAS. In Exp. I, the DMI range was 1.16 to 1.84% of BW and did not affect (P > 0.05) the apparent RNA digestibility in the small intestine, which had a mean of 75.6%, and a true digestibility of 93.0%. The mean ratio of the N-RNA to the total-N in the ruminal bacteria was 0.137. The daily urinary PD excretion (Y, mmol/kg of BW(0.75)) was a function of RNA flow in the abomasum (X, mmol/kg of BW(0.75)): Y = 0.860X + 0.460, where 0.860 and 0.460 were the PD recovery of purines and the endogenous fraction (in mmol/kg of BW(0.75)), respectively. In Exp. II, the daily urinary PD excretion was a function of RNA flow in the abomasum: Y = 0.741X + 0.301, where 0.741 and 0.301 were the recovery of PD in urine of infused purines and the endogenous losses (in mmol/kg of BW(0.75)), respectively. In conclusion, our data suggest that in Nellore heifers the respective values of endogenous PD excretion (mmol/kg of BW(0.75)), urinary recovery of the purines absorbed in the abomasum, and true digestibility of RNA in the small intestine were 0.30, 0.80, and 0.93.

Potential of Sarson Saag Waste-a Cannery Waste as Ruminant Feed

The nutritional worth of Sarson Saag Waste (SSW), a cannery waste, was assessed in comparison with conventional complete diet as a total mixed ration (TMR), and a conventional green fodder, Avena sativa. Each diet was offered ad libitum, supplemented with mineral mixture and common salt, to 4 male murrah buffaloes. The control TMR was made iso-nitrogenous to SSW. Simultaneously, each diet was offered to 3 rumen fistulated male buffaloes for assessing the biochemical changes in the rumen. The nutrient digestibility of unconventional SSW was comparable to that of conventional green fodder-A. sativa but significantly (p<0.05) higher than that of control TMR. The tri-chloro acetic acid (TCA) precipitable-N in the strained rumen liquor of animals fed SSW was considerably higher than that of animals fed A.sativa. The urinary excretion of total purine derivatives was comparable in animals fed SSW and conventional green fodder but significantly (p<0.05) higher than those fed conventional control TMR. The significantly (p<0.05) lower purine nitrogen index (PNI) in animals fed control TMR resulted in significantly (p<0.05) lower microbial protein synthesis than that in animals fed SSW and conventional green fodder. The N-excretion as per cent of nitrogen intake was significantly (p<0.05) lower in animals fed SSW as compared to either of the conventional feeds tested, resulting in significantly (p<0.05) higher N- retention and apparent biological value. SSW supplemented with mineral mixture could serve as an excellent source of nutrients for ruminants. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 4 : 479-482)

Castor bean meal for cattle finishing: 1—Nutritional parameters

This study was carried out to evaluate the effects of replacing soybean meal (SM) with castor bean meal supplemented (CBT) or not (CBNT) with calcium oxide on the intake, total, ruminal and intestinal apparent digestibility of dietary contituents, ruminal pH, and nitrogen ammonia concentration (NH 3-N), ruminal degradation parameters, and on the ruminal microbial protein synthesis based on urinary purine derivatives excretion or purine bases in the abomasum. Were used 5 Bos indicus crossbreed castrated male cattle were used with average initial body weight of 360 ± 30 kg, fistulated in the rumen and the abomasum, in a 5 × 5 Latin square experimental design. The duration of each experimental period was 14 d, with 8 d of adaptation and 6 d of sampling. The 5 treatments consisted of 4 levels of replacement of SM with CBT (0, 33, 67 and 100% on the DM basis) and one treatment with 100% replacement of SM with CBNT. The diet consisted of 35 and 65% of concentrate and corn silage on the DM basis, respectively. It was verified that DM digestibility was reduced ( P < 0.05) by alkaline treatment of the castor bean meal. With the exception to ruminal apparent digestibility of crude protein (RDCP), there was no effect of calcium oxide ( P > 0.05) on the digestibility of other constituents. We observed an increase in RDCP of 24.2% ( P < 0.05) for the CBNT treatment compared to the CBT. The intestinal digestibility of the dietary constituents was not affected by the percentage of SM replaced with CBT. However, alkaline treatment of the CBNT decreased ( P < 0.05) the intestinal apparent digestibility of ether extract. There was no interaction ( P > 0.05) between treatment and time for ruminal pH; however, ruminal pH was influenced ( P < 0.05) by collection time, with a minimum value of 6.23 estimated at 5.8 h after food delivery. However there was an interaction ( P < 0.05) between treatment and collection time for NH 3-N concentration. There were no observed differences ( P > 0.05) in excretion of nitrogenous compounds in the urine among the different castor bean meal treatments. The N-RNA to total microbial N ratio was not affected by the percentage of CBT, presenting an average of 0.138. No differences were detected ( P > 0.05) between the two methods used to estimate the ruminal microbial protein synthesis. We conclude that castor bean meal supplemented with 60 g kg − 1 of calcium oxide can fully replace soybean meal in crossbreed finishing cattle diets.

Nitrogen utilization, nutrient digestibility, and excretion of purine derivatives in dairy cattle consuming rations containing corn milling co-products

The objectives of this experiment were to determine the effects of feeding a combination of modified wet distillers grains with solubles (WDGS) and wet corn gluten feed (WCGF) on nutrient digestion, purine derivative excretion, and N utilization. Multiparous (n=20) and primiparous (n=20) cows were arranged in a replicated 5 × 5 Latin square with 21-d periods. Animals were fed one of 5 treatment diets during each period: 1) 0% co-products (control); 2) 15% WDGS (15WDGS); 3) 15% WCGF (15WCGF); 4) 7.5% WDGS and 7.5% WCGF (15MIX); and 5) 15% WDGS and 15% WCGF (30MIX; dry matter basis). A portion of forages, corn, and soy-based protein was replaced with WDGS, or WCGF, or both. Dry matter intake was greater for 15WDGS (25.1 kg/d) and 30MIX (25.5 kg/d) than for control (22.4 kg/d), 15WCGF (23.2 kg/d), or 15MIX (23.5 kg/d). Dry matter digestibility was greatest for 15WCGF and 30MIX (63.6 and 64.1%, respectively) and least for 15WDGS (59.8%), and neutral detergent fiber and N digestibility were greatest for 30MIX (50.7 and 68.6%, respectively) and lowest for 15WDGS (41.3 and 61.5%, respectively). Excretion of purine derivatives in urine was greater for co-product treatment diets than for control. Fecal N was greatest for 15WDGS compared with other treatment diets (311.0 vs. 263.3 g/d), whereas urinary N was greatest for 30MIX (330.0 g/d), intermediate for 15WCGF and 15MIX (319.3 and 320.5 g/d, respectively), and lowest for control and 15WDGS (308.5 and 312.2 g/d, respectively). Manure N (fecal+urinary N) was greatest for 15WDGS, intermediate for 15MIX and 30MIX, and lowest for control and 15WCGF. Treatment diets did not differ in 4% fat-corrected milk production. Compared with the ration containing WDGS, the ration with a 30% mixture of WDGS and WCGF improved nutrient digestibility and N utilization with reduced manure N excretion and increased N retention. Thus, it appears feeding WDGS and WCGF in combination reduces some of the negative effects of feeding WDGS alone.