Excretion Of Purine Derivatives Research Articles

Estimation of microbial protein synthesis in the rumen of growing lambs based on the purine derivative excretions and the dietary forage-to-concentrate ratio.

Estimating microbial protein synthesis (MPS) in the rumen of growing lambs based on the urinary excretion of purine derivatives (PDs) and forage to concentrate (F/C) ratio. 36 similar-growing male lambs (weight 32.53 ± 1.90 kg; age 93 ± 6.63 days) were used in a completely randomized design with four groups: a) the 20-80 F/C ratio (dry hay 10% + wheat straw 10%), b) the 20-80 F/C ratio (dry hay 0% + wheat straw 20%), c) the 10-90 F/C ratio (dry hay 5% + wheat straw 5%), d) and the 10-90 F/C ratio (dry hay 0% + wheat straw 10%) with nine replicates. Total PD and rumen MPS synthesized increased (10.98 vs. 13.25 mmol/day and 59.45 vs. 71.80 gm/day) in group d compared to group a. Dry organic matter intake (0.869 kg/day), fermentable dry organic matter (0.563 kg/day), and microbial nitrogen (N) yield (11.48 gm/day) of group d were at the maximum, but in terms of gN/kg dry organic matter (22.37 gm/kg), the mean of group c was higher than others. Increasing the level of food concentrate and the gradual removal of alfalfa from the diet increased the excretion of PD and MPS in the rumen. It was also found that urinary PD monitoring is an accurate indicator for the estimation of MPS.

Effect of Dietary Inclusion of Riboflavin on Growth, Nutrient Digestibility and Ruminal Fermentation in Hu Lambs

The study evaluated the influences of riboflavin (RF) supply on the growth performance, nutrient digestibility and ruminal fermentation in lambs. Forty-eight Hu lambs were randomly assigned into four groups receiving RF of 0, 15, 30 and 45 mg/kg dry mater (DM), respectively. Increasing RF supply did not affect the DM intake, but quadratically increased the average daily gain and linearly decreased feed conversion ratio. Total-tract DM, neutral detergent fibre, acid detergent fibre and crude protein digestibility increased quadratically. Rumen pH and propionate molar percentage decreased linearly, total volatile fatty acids concentration, acetate proportion and the ratio of acetate to propionate increased linearly, but ammonia nitrogen concentration was unchanged with increasing RF supply. Linear increases were observed on the activities of carboxymethyl-cellulase, xylanase, pectinase and protease, and the populations of bacteria, fungi, protozoa, dominant cellulolytic bacteria, Ruminobacter amylophilus and Prevotella ruminicola. Methanogens population was not affected by RF supplementation. The microbial protein amount and urinary total purine derivatives excretion increased quadratically. The results indicated that 30 mg/kg DM RF supply improved growth performance, rumen fermentation and nutrient digestion in lambs.

Effect of supplementing sulphate-reducing bacteria along with sulphur on growth performance, nutrient utilization and methane emission in goats

A competitive relationship exists between sulphate-reducing bacteria and methanogens in the anaerobic environment including rumen for hydrogen where sulphate is not limiting growth and consequently inhibit enteric methane emission as thermodynamically energetic sulphate reduction (∆Go = - 21.1kJ/mole of H2) is more favourable than methanogenesis (∆Go = - 16.9kJ/mole H2). To validate this hypothesis, a study was designed to investigate the effect of supplementation of sulphate-reducing bacteria (SRB) identified as Streptococcus caviae RM296 as microbial feed additives alone or along with sulphur (as sodium sulphate) on methane production, live weight gain, feed intake, nutrient digestibility and energy metabolism in goats. The experiment was conducted on growing kids (n = 36, 5-6months of age) with average body weight of 10.08 ± 0.21kg, divided into six groups (n = 6). The duration of the feeding trial was of 150days. The six treatments were control fed a basal diet (T1), SRB 0.5ml/kg BW (T2), sulphur (as sodium sulphate) 0.095% of DMI (total sulphur level in the diet 1.5 times the requirement) (T3), sulphur (as sodium sulphate) 0.095% of DMI + SRB 0.5ml/kg BW (T4), sulphur (as sodium sulphate) 0.19% of DMI (total sulphur level in the diet 2 times the requirement) (T5) and sulphur (as sodium sulphate) 0.19% of DMI + SRB 0.5ml/kg BW (T6). Duration of study was 150days and goats were fed as per ICAR (2013) feeding standard. Methane (CH4) production (l/kg DMI) was reduced by 11.8% (P = 0.052) in T6 where sulphur (0.19% DMI) was supplemented along with SRB4 (at the rate 0.5ml/kg BW) as compared to T1 (un-supplemented group). However, the dry matter intake (DM), total weight gain (TG), average daily gain (ADG), feed conversion ratio (FCR), excretion of purine derivatives (allantoin, uric acid, xanthine and hypoxanthine) and digestibility of organic matter (OM), dry matter (DM), ether extract (EE), crude protein (CP), acid detergent fibre (ADF) and neutral detergent fibre (NDF) were similar (P > 0.05) among all the groups. The experimental data revealed that feeding of SRB as a microbial feed additive along with sulphur (as sodium sulphate) is capable of reducing enteric CH4 emission without any adverse effect on rumen fermentation and digestibility of the nutrients.

Dietary protein oscillation: effects on digestibility, nutrient balance and estimated microbial protein synthesis in lactating dairy cows

Various studies with growing ruminants report increases in nitrogen use efficiency (NUE) when feeding oscillating (OS) dietary CP, whereas limited research with lactating dairy cows demonstrates a lack of improvement in NUE when feeding OS diets. We hypothesised that a total mixed ration (TMR) delivering OS CP (48-h phases of 134 and 171 g CP/kg DM, respectively) compared to a static CP TMR (ST; 152 g CP/kg DM) would result in similar or increased urinary purine derivative excretion (as a marker of microbial protein synthesis (MPS)) and greater urinary nitrogen excretion in lactating dairy cows. Responses in intake, production, apparent total tract digestibility (ATTD), nutrient balance, and estimated MPS were evaluated using faecal and urine collection in 12 multiparous cows (172 ± 39 d in milk) in a randomised complete block design, where total urinary output was estimated indirectly. All measurements were taken during d 8 (at 1700) to d 16 (at 1700) of the 16-d study that followed a 28-d period in which cows already received their respective treatments. Dry matter intake, yields of milk, protein, fat, lactose, and fat- and protein-corrected milk were similar for ST and OS. Milk composition, BW, and body condition score also did not differ between treatments, except for a tendency for increased milk urea concentration with OS (13.7 vs 12.4 mg/dL). Feed efficiency, NUE and ATTD of organic matter, NDF, CP and gross energy did not differ, but ATTD of crude fat (658 vs 627 g/kg) and starch (980 vs 975 g/kg) increased, and ATTD of DM (702 vs 691 g/kg) tended to increase with OS. Milk energy as a proportion of digested energy tended to decrease with OS (34.6 vs 37.1%), but other energy metabolism variables were not affected by treatment. Estimated urinary nitrogen excretion increased (165 vs 144 g/d), estimated urinary nitrogen as a proportion of nitrogen intake tended to increase (25.3 vs 22.7%), and milk nitrogen as a proportion of digested nitrogen decreased (47.3 vs 51.8%) in response to OS. Estimated urinary excretion of creatinine (184 vs 165 mmol/d), uric acid (29 vs 20 mmol/d) and urea (3.1 vs 2.5 mol/d) increased, but other nitrogen metabolism parameters were not affected by OS. Overall, oscillating dietary CP content did not affect lactational performance, milk NUE, or estimated MPS. However, ATTD of some nutrients increased, postabsorptive energy use for milk synthesis tended to decrease, and estimated urinary nitrogen losses increased with OS.

Dietary polymer-coated urea enhances the goats lactational performance, excretion of microbial purine derivatives and blood metabolites in the semi-arid zone of Iran

This study aimed to determine the effect of using different sources of nitrogen to supply part of degradable intake protein needs in lactating goat performance and its effect on excretion of microbial purine derivatives and blood metabolites. Thirty-two lactating Saanen goats (body weight 38.85 ± 2.14 kg and 1979 ± 0.25 g day-1 milk yield) were used in a one-way ANOVA completely randomized design. Goats were assigned to the following treatments for a 10-wk experimental period: 1) Control (canola meal as a nitrogen source); 2) Urea (0.5% urea); 3) Optigen (0.55% Optigen- Alltech. Inc., Lexington, KY) and 4) Polymer-Coated Urea (PCU- international patent number: A01K5/00, 0.7% PCU) based on dry mater intake. Non-protein nitrogen groups had a comparative effect (p > 0.05) between control and other treatments on milk composition, microbial protein synthesis and they affected on blood factors including urea, cholesterol, and ALT. Dry matter intake decreased (p > 0.05) in PCU, Optigen, Urea than Control goats. Synthesis of microbial protein in PCU goats was 22.5 g day-1 and it was greater (p > 0.05) than other treatments. Plasma cholesterol was increased in PCU and Optigen, whereas urea concentration was increased in Urea and Control goats. Milk production was higher in PCU than Urea and Control. Feed conversion ratio was improved (p > 0.05) in PCU and Optigen goats versus other treatments. This study demonstrated that polymer-coated urea can be utilized as a nitrogen source and improve goats milk performance.

Influence of encapsulated pepper on ruminal fermentation, nutrient digestibility, and performance in dairy cows

The aim of this study was to evaluate the effects of a feed additive containing encapsulated pepper on total-tract apparent nutrient digestibility, sorting index, ruminal fermentation, milk yield and composition, serum concentrations of urea-N and glucose, purine derivative excretion, and N utilization efficiency in dairy cows. Twenty-two Holstein cows (182 ± 86.3 days in milk, 35.4 ± 4.85 kg/d milk yield), of which 4 were rumen cannulated, were used in a crossover design experiment with 21-d periods (14 days allowed to treatment adaptation and 7 days for sampling). Cows were blocked according to parity, days in milk, and milk yield and randomly assigned to the following treatments: Control (CON), or 1.5 g/d (CAP) of a feed additive containing encapsulated pepper (Capcin; NutriQuest, Campinas, Brazil) added to the concentrate along with minerals. Data were analyzed using the mixed procedure of SAS modeling the fixed effects of treatment, period, and the random effect of animal. Ruminal fermentation data were analyzed as repeated measurements adding the fixed effect of time and its interaction with treatments to the previous model. No differences in intake of dry matter or nutrients were detected. Sorting for feed particles between 19 and 8 mm size was greater in cows fed CAP compared to CON (1.000 and 0.992 kg/kg, respectively). Feeding CAP had no effects on digestibility of dry matter, crude protein, ether extract, or neutral detergent fiber. Nor treatment or interaction effect between treatment and time were observed for ruminal pH, NH3N concentration, or short-chain fatty acids concentration. Yields of milk (35.3 vs 34.3 kg/d) and fat-corrected milk (37.4 vs 36.0 kg/d) were greater for cows under CAP treatment compared to CON. Yield of milk solids (fat, protein, and lactose) was increased when feeding CAP. Milk fat concentration tended to be greater in cows fed CAP than those in CON group (39.5 vs 38.3 g/kg, respectively). Feed efficiency (fat-corrected milk ÷ dry matter intake) tended to be greater in cows fed CAP than CON-cows (1.45 vs 1.40, respectively). Serum concentrations of urea-N and glucose were similar between treatment groups. Feeding CAP did not alter purine derivative excretion (allantoin in urine and milk, and uric acid in urine), as well as the nitrogen excreted (g/g N intake) through feces, milk, or urine. In conclusion, feeding CAP at 1.5 g/d improved performance without altering nutrient digestibility, ruminal fermentation, excretion of purine derivatives, or efficiency of nitrogen utilization in dairy cows.

Feeding encapsulated pepper to dairy cows during the hot season improves performance without affecting core and skin temperature.

Peppers (Capsicum spp.) contain capsaicin, an organic compound with a group of alkaloids that has shown thermoregulation properties in humans and mice, and may influence glucose and lipid metabolism in ruminants. An experiment was conducted to evaluate different doses of a feed additive containing encapsulated pepper on milk yield and composition, dry matter intake, feed sorting index, total-tract apparent digestibility of nutrients, purine derivatives excretion, and serum concentrations of urea-N and glucose, N excretion, respiration rate, rectal temperature, and skin temperature in different regions (forehead, face, and rumen). Thirty-six Holstein cows (150 ± 102.1 d in milk and 29.3 ± 5.81 kg/d milk yield) were used in a 9-wk randomized complete block (n = 12) design experiment. Following a 2-wk covariate period, cows were blocked according to parity, days in milk, and milk yield and were randomly assigned to the following treatments: 0 (CAP0), 0.75 (CAP75), or 1.5 (CAP150) g/d of a feed additive containing encapsulated pepper (1 g/kg, Capcin; NutriQuest) added to the concentrate along with minerals. Treatment differences were evaluated through orthogonal contrasts (CAP0 vs. CAP75 + CAP150 or CAP75 vs. CAP150). The average temperature-humidity index during the experiment was 72.0 ± 2.07. Dry matter intake was greater in cows fed a feed additive containing encapsulated pepper (CAP) treatments (CAP75 and CAP150) compared with CAP0. Cows fed CAP150 tended to have greater dry matter intake than those in CAP75 group. Feeding CAP decreased sorting for feed particles with size between 8 and 4 mm. An interaction effect between treatment and week was observed for crude protein digestibility whereas cows fed CAP150 had the greatest digestibility on the third week of experiment. Orthogonal contrasts did not detect differences in serum concentrations of glucose and urea-N, or purine derivatives excretion. Nitrogen excretion (as % of N intake) in milk, urine, and feces was not altered by treatments. Feeding CAP increased yields of 3.5% fat-corrected milk, fat, protein, and lactose. A tendency toward greater milk protein content was observed for cows fed CAP150 than CAP75. No differences were detected on respiration rate, rectal temperature, and skin temperature of cows. A feed additive containing encapsulated pepper fed at 0.75 or 1.5 g/d can improve yield of fat-corrected milk and milk solids by increasing feed intake without affecting nutrient digestibility and body temperature of lactating cows during the hot season.

Growth performance, nutrient digestibility, and ruminal fermentation of dairy calves fed starter diets with alfalfa hay versus corn silage as forage and soybean oil versus palm fatty acids as fat source.

The present study was intended to evaluate the effect of forage source (alfalfa hay; ALF vs. corn silage; CS) along with a supplemental fat source (soybean oil; SO vs. rumen-inert palm fatty acids; PF) on growth performance, nutrient digestibility, and ruminal fermentation in dairy calves. Forty-eight new-born Holstein female calves (3 d old) were assigned to one of 4 treatments: (1) alfalfa hay with soybean oil (ALF-SO); (2) alfalfa hay with palm fatty acids (ALF-PF); (3) corn silage with soybean oil (CS-SO); (4) corn silage with palm fatty acids (CS-PF). Starter diets had equal amounts of forage (100 g/kg dry matter; DM) and fat source (30 g/kg DM). Calves were fed a constant amount of milk (d 1 to 63) and had ad libitum access to water and starters (d 1 to 83). The lowest and greatest starter intakes during the preweaning period occurred in ALF-SO and CS-PF, respectively. This coincided with forage × fat source interaction for average daily gain (ADG) during preweaning. The forage source affected total DM intake and ADG over the entire period, body weight (BW) at weaning, and final BW with greater values in calves that received CS compared with ALF. The concentrations of total short-chain fatty acids and butyrate were increased, whereas concentration of acetate and acetate:propionate ratio were decreased in the rumen of calves fed CS compared with ALF. Feeding CS increased urinary excretion of allantoin and, as a trend, total purine derivatives (PD) and estimated microbial protein synthesis in comparison with ALF. The fat source affected starter intake, ADG, and BW postweaning with the highest values in PF. The digestibility of neutral detergent fiber, crude protein and, as a trend, organic matter were higher in calves fed PF compared with SO. Calves fed PF had lower ruminal ammonia-N concentration and urinary N excretion and greater urinary excretion of allantoin and total PD. Calves receiving SO had a lower ruminal protozoa population. In conclusion, supplementing starter diets with CS and PF is superior to ALF and SO. Interaction of the positive effects of CS and PF on performance underlines that concurrent supplementation of CS with PF is especially recommendable in young calves before weaning.

Defatted silkworm pupae meal as an alternative protein source for cattle.

Silkworm pupae meal (SWP) is a protein-rich by-product of the silk reeling industry, available in a significant quantity. However, there has been little and insignificant research into the use of SWP in ruminants to date. In this view, the present study was conducted in two phases to evaluate the effect of different inclusion levels of defatted silkworm pupae meal (DSWP) on rumen fermentation, microbial protein synthesis and nutrient utilisation in cattle fed on finger millet straw (FMS)-based diet. Four isonitrogenous concentrate mixtures (CM) were prepared with DSWP replacing soybean meal (SBM) protein at 0 (T0), 10 (T1), 20 (T2) and 30% (T3). In phase I, a rumen fermentation experiment was conducted in a 4 × 4 Latin square design using four crossbred steers to study the effect of different levels of DSWP on rumen fermentation. No significant difference (P > 0.05) was observed in rumen fermentation parameters such as pH, ammonia nitrogen (NH3-N) and total volatile fatty acids (VFA) among the experimental groups. In phase II, the digestibility trial was conducted in 20 crossbred cattle (311.2 ± 4.81kg), which were divided into four experimental groups of five animals each in a completely randomised design to study the effect of different rations (T0, T1, T2, T3) on microbial protein synthesis and nutrient utilisation. The intake and digestibility of nutrients, excretion of urinary purine derivatives and microbial protein synthesis were not significantly different among the experimental groups. In addition, feeding DSWP revealed no significant (P > 0.05) change in the blood biochemical parameters of animals. Furthermore, at the same price as SBM, DSWP provides two units more crude protein. Therefore, the results of the present study indicated that DSWP can be incorporated into the ration of cattle up to 30% by replacing SBM without affecting rumen fermentation pattern and nutrient utilisation.

Creatinine as a Urinary Marker of the Purine Derivatives Excretion in Urine Spot Samples of Lambs Fed Peach Palm Meal.

Simple SummaryExperimental trials designed to predict the microbial protein synthesis in the rumen via urinary purine derivatives require access to 24-h urinary volumes. This technique is non-invasive but requires access to 24-h urinary volumes, which is impracticable in grazing animals or a large number of feedlot sheep. The challenge is to provide the possibility of using the purine derivatives and creatinine concentrations in a spot urine sample and the daily creatinine excretion in urine as accurate estimators of purine derivatives’ excretion per day.The objective was to evaluate the influence of diets on lambs using different levels of peach palm meal as a replacement for maize (0, 10, 40, 60, and 85% of diet dry matter) on the endogenous creatinine clearance (CC), urine concentration ratio of purine derivatives to creatinine (PDC index), and daily creatinine excretion (DCE) as a marker to estimate purine derivatives (PD) excretion from urinary spot samples collected at different time points (4, 8, 12, 16, 20, 24 h after morning feeding) compared to 24-h total urine collection. The measured parameters were voluntary intake, urinary volume, CC, DCE, the concentration of plasma creatinine, and PD and purine derivatives’ excretion (PDE). Five lambs were allocated to metabolic cages and distributed in a 5 × 5 Latin square. Urine collection was taken daily on days 16 to 19 of each experimental period. The inclusion of peach palm meal linearly reduced the intake of dry matter (g kg BW−0.75, p = 0.005), crude protein (g kg BW−0.75, p = 0.010), metabolizable energy (MJ kg BW−0.75, p = 0.010) and CC (p < 0.0001). It also quadratically affected the urinary volume (p = 0.008) and DCE (p = 0.004). There was a linear decrease for PDC index (p = 0.032) and PDE (p < 0.0001) measured in the 24-h total urine with peach palm meal levels. The different times of spot urine sampling did not affect (p > 0.05) the PDC index and PDE. Peach palm meal decreases the CC thereby compromising the use of a mean value of DCE as a PDE marker in spot urine samples. There is greater accuracy when using different values of DCE obtained for each diet as markers for the PDE in spot urine samples. Unconventional foodstuffs of low palatability affecting the voluntary intake of feed change the renal function.

Changing the grazing session from morning to afternoon or including tannins in the diet was effective in decreasing the urinary nitrogen of dairy cows fed a total mixed ration and herbage

Our aim was to evaluate whether increasing soluble carbohydrates in the herbage by changing the time of the grazing session or including Acacia mearnsii tannin in the diet would affect intake, digestion, N partitioning, and productive performance of dairy cows fed a diet combining ryegrass herbage with partial total mixed ration (PMR). We hypothesized that both strategies could reduce the concentration of NH3-N in the rumen, reducing urinary N excretion. Nine Holstein cows were used in a triplicate 3 × 3 Latin square experiment with 3 experimental periods of 22 d. The cows were fed a fixed amount of PMR [60% of the predicted individual dry matter intake (DMI)], and an unrestricted amount of herbage in 1 grazing session of 5 h/d. The treatments were (1) morning grazing session and afternoon PMR meal (AM); (2) morning PMR meal and afternoon grazing session (PM); and (3) morning grazing session and afternoon PMR meal supplemented with 15.0 g of tannins/kg of PMR dry matter (TAN). Milk production was not affected by treatments. Although the protein concentration was lower for TAN than for PM, no differences were detected for the yield of any component between treatments. The concentration of individual or grouped fatty acids in milk fat was not affected by treatments, except for 16:1 cis-9 and Δ9-desaturase ratios 14:1/14:0 and 16:1/16:0, which were lower for TAN. Treatments did not affect total DMI, but PM tended to increase herbage DMI and reduce dry matter and crude protein digestibilities. Treatments did not affect cow eating and ruminating behavior except for the proportion of time spent eating PMR, which was higher for PM and TAN. Although no relevant effects of treatments on ruminal fermentation, purine derivatives excretion in urine, or N excretion in milk were detected, both PM and TAN decreased the total N excreted in urine by an average of 8% compared with AM. In conclusion, changing the grazing session from the morning to the afternoon and including tannins in the diet were effective in decreasing the excretion of urinary N but did not change the productive performance of dairy cows fed PMR and ryegrass herbage.

Increasing doses of biocholine on apparent digestibility, ruminal fermentation, and performance in dairy cows

Biocholine is an herbal feed additive considered a natural alternative to synthetic choline, with relatively low rumen degradability composed of cellulose and choline conjugates, namely phosphatidylcholine. Rumen-protected choline has been largely evaluated during the peripartum period, but few studies evaluated the effects of choline supplementation after the transition period. The objective of this study was to determine the effects of increasing doses of biocholine on feed intake, feed particle sorting, total apparent digestibility, ruminal fermentation, milk yield and composition, purine derivative excretion, and nitrogen balance. Twenty-four Holstein cows (163 ± 98 days in milk, 27.6 ± 7.14 kg/d milk yield), 4 of which were ruminally cannulated, were enrolled to this study. Cows were blocked according to milk yield, days in milk, and presence of ruminal cannulas, then all cows were randomly assigned to a treatment sequence in a replicated 4 × 4 Latin square experiment design. The experimental treatments were a control (CON) diet, and biocholine (BC; Biocholine FC®, Nutriquest Technofeed Nutrição Animal Ltda., Campinas, Brazil) fed at 7, 14, and 21 g/d. Cows were allowed 14 d of adaptation to treatments and the last 7 days of each period were used for sampling. The forage to concentrate ratio of the basal diet was 48:52 (on a dry matter basis) with corn silage as the single forage source, and diet was provided in the form of total mixed ration. No treatment effects were detected on feed intake, but BC quadratically affected (P = 0.010) sorting for feed particles >19 mm and linearly increased (P = 0.037) ether extract digestibility (840, 834, 843, and 853 g/kg for cows fed BC at 0, 7, 14, and 21 g/d, respectively). Biocholine supplementation tended to quadratically decrease ruminal pH (6.17, 6.04, 6.11, and 6.11 for cows fed BC at 0, 7, 14, and 21 g/d, respectively) but had no effect on concentrations of total volatile fatty acids and NH3-N. Biocholine had a positive quadratic effect (P ≤ 0.042) on milk yield (29.5, 30.5, 30.0, and 29.8 kg/d for cows fed BC at 0, 7, 14, and 21 g/d, respectively) and feed efficiency (1.20, 1.25, 1.21, and 1.21 kg milk/kg DM intake for cows fed BC at 0, 7, 14, and 21 g/d, respectively). Biocholine tended to quadratically affect (P = 0.058) N excretion through milk (157, 162, 160, and 159 g/d for cows fed BC at 0, 7, 14, and 21 g/d, respectively). There was no evidence for treatment effects on purine derivatives excretion. In conclusion, feeding BC may improve milk yield and feed efficiency of dairy cows. Predicted maxima response in milk yield and feed efficiency were observed at 10 g/d of BC.

SÍNTESE DE PROTEÍNA MICROBIANA E BALANÇO DE NITROGÊNIO EM NOVILHAS MESTIÇAS HOLANDEZ /ZEBU ALIMENTADAS COM DUAS FONTES DE TANINOS

Tannins have been used to trigger positive effects on ruminal metabolism. So, increasing levels of tannic acid in a sorghum-based diet for five Holstein/Zebu crossbred lactating heifers were subject to a 5 × 5 Latin square experimental design, five heifers x five tannins acid levels x five periods. The excretion of total purine derivatives, through the collection of spot urine samples, and the N concentration values in the milk and urine were used. All heifers received 9.87 kg/DM of corn silage as roughage and 6.38 kg of concentrate (not fed ad libitum). Diet 1 (control) contained low-tannin sorghum (0.027kg total tannin), and the other diets contained high-tannin sorghum. The levels of tannic acid added used were established based on the quantity of condensed tannin in high-tannin sorghum. Thus, diets 2, 3, 4, and 5 were supplemented with 1.5g (13.%DM), 79.5g (2.6%DM), 157.5g (3.9%DM), and 235.5g (5.2%DM) of tannic acid totalling 0.078, 0.156, 0.234, and 0.321 total tannin kg/day respectively. The urinary excretions of urea (2.0055), total allantoin (185.12 mmol/day-1) , and total purine derivatives (222.32 mmol/day-1); absorbed purines 179.3 mmol/day-1); the N microbian synthesis (130.358 (g)N/day-1); and the concentrations of allantoin in milk (36.40 mmol/day-1) were not affected by the diets. Diets using two tannins sources supplementation did not affect the animal’s health, that is, it did not change the blood and metabolic rates above the normality indices for the animal category, neither improved the efficiency of the microbial synthesis nor the balance of N for milk production

Feeding mango wastes to dairy goats: Effects on diet digestibility, ruminal fermentation, and milk yield and composition

The aim of this study was to assess the potential of mango wastes (0.65:0.35 pulp:peels mixture, PP) preserved in multinutrient blocks (MMB) for goats feeding that replaced part of a commercial concentrate for dairy goats, and contained 0.29 of the mango PP. The multinutrient blocks were formulated to have similar protein content than the concentrate. In addition, soybean meal was totally replaced with sunflower meal. Two diets composed of 0.4 of alfalfa hay and either 0.6 of a commercial concentrate (control diet) or 0.4 of concentrate and 0.2 of MMB (MAN diet) were fed to two homogeneous groups of Murciano-Granadina dairy goats of 8 animals each. Feed intake, diet digestibility, milk yield, composition and fatty acid (FA) profile, ruminal fermentation parameters, and urinary excretion of purine derivatives were measured. The daily intake of MMB averaged 83.9 g dry matter (DM) per goat and was accompanied by an average daily decrease of 71.0 g in concentrate intake (P = 0.324) and 41.0 g of increase in alfalfa hay intake. However, there were no differences between groups (P ≥ 0.253) in the intake of total DM, nitrogen and gross energy. Similarly, nutrient digestibility, utilization of both nitrogen (N) and energy, and urinary excretion of purine derivatives were similar (P ≥ 0.103) for both diets. Partial replacement of concentrate with MMB did not affect (P ≥ 0.358) milk yield and composition, but the milk from MAN-fed goats had greater (P = 0.038) saturated FA and lower (P = 0.047) polyunsaturated FA proportions than the milk from goats fed the control diet. Feeding the MAN diet also resulted in greater (P = 0.003) proportions of milk FA with less than 16 carbons and lower (P = 0.009) proportions of FA with more than 16 carbons compared with feeding the control diet. Similar values (P ≥ 0.213) of ruminal pH and concentrations of NH3-N and total volatile fatty acids were registered in both groups of animals, but goats fed the MAN diet had lower (P = 0.003) acetate and greater (P = 0.029) propionate proportions than those fed the control diet. Under the circumstances of the present study, the profit of milk production (€/d) tended (P = 0.056) to be greater for the MAN diet compared with the control diet. Although multinutrient blocks seem to be a feasible option to preserve mango wastes, more studies are needed to increase the intake of MMB by goats.

Excreção de creatinina e derivados de purina e síntese microbiana em cordeiros alimentados com farinha de vagem de Samanea saman

ABSTRACT Evaluated the levels of rain tree (Samanea saman) pod meal (RTPM) (0, 10, 15, 20 and 25%) replacing maize in the dry matter of the diet on intake of DM, CP and ME, creatinine and total purine derivatives excretion in urine and microbial protein synthesis in lambs. Twenty-five uncastrated Bergamasca lambs were used, with an initial body weight of 24±5kg and an average age of 120 days. The experimental design was completely randomized, with five treatments and five replications. The trial lasted 84 days and the 24h and spot urine collections were performed in the last day of the experiment. The intake was not affected (P&gt;0.05), the urine volume and daily creatinine excretion were influenced (P&lt;0.05) by RTPM replacing maize, observing increasing linear effect and cubic variation (P&lt;0.05), respectively. The cubic and quadratic components were significant (P&lt;0.05) for the excretion of total purine derivatives, absorbed purines, and microbial synthesis. The cubic variation, with peaks at 5% and 18% replacement for urinary excretion of creatinine and purine derivatives, indicates that the levels used of RTPM affected the renal activity of lambs. Substitution of maize by RTPM up to 10% enhances efficiency of rumen microbial crude protein synthesis.

Milk feeding level and starter protein content: Effects on growth performance, blood metabolites, and urinary purine derivatives of Holstein dairy calves

The objective of this study was to investigate the effects of milk allowances equal to 526 g/d as moderate (MOD) versus 790 g/d of milk dry matter as high (HI), and starter diets containing 18% or 23% crude protein (CP), on growth performance, blood metabolites, and purine derivative (PD) excretion in the urine of dairy calves. A total of 52 female Holstein dairy calves (40.8 kg of body weight) were randomly assigned to the experimental diets. The treatments were (1) moderate milk and 18% CP starter diet (MOD-18CP); (2) MOD and 23% CP starter diet (MOD-23CP); (3) high milk and 18% CP starter diet (HI-18CP); and (4) HI and 23% CP starter diet (HI-23CP). Calves had free access to a starter feed and water and were weaned on d 53 but remained in the study until d 73. Urine samples were collected during the preweaning period (for 6 consecutive days between d 35 and 40) and postweaning period (for 6 consecutive days between d 65 and 70) to investigate urinary excretion of PD. Starter feed intake, β-hydroxybutyrate (BHB), and blood urea concentrations were reduced; however, average daily gain (ADG) and blood glucose levels increased in calves fed HI before weaning compared with MOD. During the preweaning period, high milk feeding increased total urinary PD excretion but decreased it after weaning. The 23CP diet resulted in higher feed intake and ADG before weaning and higher excretion of allantoin and total excretion of PD compared with the 18CP diet. The HI-23CP treatment resulted in the greatest withers and hip heights at weaning and final measurement, as well as the highest preweaning blood insulin concentrations. In terms of rumen development, MOD-23CP showed the greatest benefits based on starter intake, blood BHB concentration, and urinary excretion of PD. Based on the higher urinary excretion of PD found in HI-fed calves before weaning, it is possible that milk feeding overestimates estimated microbial yield. The results suggest that feeding starters with a higher proportion of CP may help maintain a more balanced ratio of CP to ME during high milk feeding, to avoid protein deficiency due to low starter intake. When calves are fed a high milk allowance, urine excretion of PD may be misinterpreted as a measure of estimated microbial growth and rumen development; this should be considered during calculations of estimated microbial yield in milk-fed calves.

Nutrient digestibility, fecal output of fractionated proteins, and ruminal fermentation parameters of goats fed a diet supplemented with spent green tea and black tea leaf silage.

Spent green and black tea leaf silage (GTS and BTS, respectively) was offered as a protein supplement to goats to examine in vivo digestibility, nitrogen balance, urinary excretion of purine derivatives, and ruminal fermentation. Four castrated goats were fed a basal diet supplemented with alfalfa hay cube (AHC), GTS, or BTS in a 4 × 4 Latin square design. Digestibilities of various nutrients except for nitrogen (N) fraction were unaffected by the type of supplement. Digestibility of acid detergent insoluble N (ADIN) in BTS treatment was a negative value and significantly lower than those in other treatments. Urinary N output and retained N were not significantly affected by the diets. The fecal output of neutral detergent insoluble nitrogen (NDIN) and ADIN in the BTS treatment was significantly higher than those in other treatments. Urinary excretion of purine derivatives was not affected by the treatments. Ruminal NH3 -N concentration in AHC and GTS treatments were not significantly different, but that in the BTS treatment was significantly lower than others. These results indicated that GTS is substitutable for AHC as a protein supplement, whereas BTS was able to bind proteins tightly in the digestive tract, which lowered ruminal N degradability and increase fecal N output.

The effect of sheep genetic merit and feed allowance on nitrogen partitioning and isotopic discrimination

Animal nitrogen (N) partitioning is a key parameter for profitability and sustainability of ruminant production systems, which may be predicted from N isotopic discrimination or fractionation (Δ15N). Both animal genetics and feeding level may interact and impact on N partitioning. Therefore, this study aimed to assess the interactive effects of genetic merit (G) and feed allowance (F) on N partitioning and Δ15N in sheep. The sheep were drawn from two levels of G (high G vs. low G; based on New Zealand Sheep Improvement Limited (http://www.sil.co.nz/) dual (wool and meat) growth index) and allocated to two levels of F (1.7 (high F) vs. 1.1 (low F) times Metabolisable Energy requirement for maintenance) treatments. Twenty-four Coopworth rams were divided into four equal groups for a N balance study: high G × high F, high G × low F, low G × high F, and low G × low F. The main factors (G and F) and the interaction term were used for 2-way ANOVA and regression analysis. Higher F led to higher N excretions (urinary N (UN); faecal N (FN); manure N), retained N, N use efficiency (NUE), and urinary purine derivatives excretion (P < 0.05). On the other hand, higher UN/N intake, and plasma Δ15N were observed with the lower F (P < 0.05). Higher G led to increased UN, FN, manure N, apparent N digestibility, and urinary purine derivatives excretion (P < 0.05). Higher F only increased UN in high G sheep, with no effect on low G sheep (P < 0.05). Regression analysis results demonstrated potential to use plasma Δ15N to reflect the effects of G and F on NUE and UN/N intake. Further research is urged to study interactive effects of genetic and feeding level on sheep N partitioning.

Effects of mild water restriction on nutrient digestion and protein metabolism in desert-adapted goats

• Mildly restricting drinking water intake by ≤ 21 % does not reduce feed intake in desert-adapted goats. • Declining drinking water intake enhances rumen fermentation, but reduces microbial growth. • Lowering drinking water intake shifts nitrogen excretion from urine to faeces. • Effects of drinking water restriction differ depending on diet and animal factors. The aim of the present study was to determine the effects of mild drinking water restriction ( WR ) on feed intake, diet digestibility, rumen fermentation, and nitrogen ( N ) balance in a desert-adapted goat breed of Oman. Two feeding trials were conducted during the dry summer months (August-October) in 2013 and 2014. In each trial, nine adult male Batinah goats were exposed to two levels of mild WR (WR: 85 % (WR15) and 70 % (WR30) of individual ad libitum consumption; 100 % (WR0)) in a 3 × 3 Latin Square design. Drinking water intake, feed offered and refused, and excretion of urine and faeces were quantified and samples analysed for crude nutrient and fibre fractions. Moreover, rumen microbial protein synthesis was estimated from urinary purine derivatives excretion. In trial 2, rumen fermentation characteristics were additionally studied in three rumen-fistulated goats. Linear and quadratic effects of WR in each trial were assessed by mixed model analysis, whereas correlations between drinking water intake and response variables were determined across both trials. For WR30, drinking water intake was 79 % and 90 %, respectively, of the water intake of WR0 goats in trial 1 and WR15 goats in trial 2. Water restriction had no effect on feed intake, rumen microbial protein synthesis, and N balance in both trials. However, apparent total tract digestibilities of neutral and acid detergent fibre tended to decrease linearly ( p ≤ 0.081) with increasing WR level in trial 1, whereas those of dry matter and organic matter were lower ( p ≤ 0.028) for WR15 than for WR0 and WR30 in trial 2. Proportions of butyrate ( p ≤ 0.046) and isovalerate ( p = 0.087) in rumen fluid were greater and those of propionate ( p = 0.079) and valerate ( p = 0.062) lower for WR30 as compared to one or both of the other WR levels. Duodenal microbial N flow and efficiency of microbial protein synthesis did not differ between WR levels. Yet, across both trials, both variables correlated positively with drinking water intake. Similarly, declining drinking water intake increased the ratio between faecal and urine N excretion (r=−0.55) and the N concentration in faeces (r=−0.42), but reduced the fibre concentration (r=0.38) and the proportion of undigested feed N in faeces (r=0.49). Mild restriction of drinking water intake to ≥ 79 % of the ad libitum consumption, which is expected to occur more frequently with advancing climate change in the semi-arid tropics and subtropics, may impair feed nutrient use and thus performance of regionally adapted small ruminants, while improving the quality of their manure.

Ruminal fermentation, microbial protein synthesis and nitrogen balance in sheep fed pistachio by-product silage

This study was conducted to evaluate the effect of feeding different levels of Pistachio pulp silage (PPS) on feed intake, nitrogen metabolism, protozoa population and purine derivative excretion in sheep. Experimental diets were different in amount of PPS. The compositions of diets given to the different treatments were as follow: (1) control (without PPS), (2) 7% PPS, (3) 14% PPS and (4) 21% PPS. Eight rams (40±2.5 kg) were used in a replicated Latin square design with four diets and four periods of 35 days each. Animals were fed with isocaloric and isonitrogenous diets. Feeding 14% of PPS enhanced significantly (p <0.05) dry matter intake, nitrogen intake and nitrogen retention in sheep. Purine derivatives excretion and so microbial protein synthesis increased (p <0.05) with adding PPS to experimental diets. Ruminal pH increased linearly with adding of PPS in this study. the Holotrich protozoa population decreased linearly by increasing level of PPS in diets (p <0.05). By increasing PPS in the experimental diets, total protozoa population and Entodinium sp., were changed quadratically (p <0.05). The highest number of protozoa population was related to 14% PPS in experimental diet. These results showed that PPS up to 14% can be used as proper source of feed for small ruminants to overcome the shortage of animal feedstuffs.