Protein Synthesis In Sheep Research Articles

A novel ammoniation treatment of barley as a strategy to optimize rumen pH, feed degradability and microbial protein synthesis in sheep.

BACKGROUNDMeeting the energy and nitrogen (N) requirements of high‐performing ruminants at the same time as avoiding digestive disturbances (i.e. rumen acidosis) is a key priority in ruminant nutrition. The present study evaluated the effect of a cereal ammoniation treatment, in which barley grains are combined with urea and enzymes that catalyze the conversion of urea to ammonia to optimize rumen function. Twelve rumen cannulated sheep were randomly divided into two groups and fed a diet containing 60% of ammoniated barley (AMM) or untreated barley supplemented with urea (CTL) to investigate the impact on rumen fermentation and feed utilization.RESULTSAMM had higher total N content and effective rumen degradable N than untreated barely. AMM sheep had a consistently higher rumen pH throughout the day (6.31 versus 6.03) and tended to have a lower post‐prandial ammonia peak and higher acetate molar proportion (+5.1%) than CTL sheep. The rumen environment in AMM sheep favored the colonization and utilization of agro‐industrial by‐products (i.e. orange pulp) by the rumen microbes leading to a higher feed degradability. AMM sheep also had higher total tract apparent N digestibility (+21.7%) and urinary excretion of purine derivatives (+34%), suggesting a higher N uptake and microbial protein synthesis than CTL sheep.CONCLUSIONThe inclusion of AMM in the diet of ruminants represents a valid strategy for maintaining rumen pH within a physiological range and improving N utilization by the rumen microbes, which could have positive effects on the health and productivity of animals in intensive production systems. These findings warrant further studies under conventional farm conditions. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Intake, nutrient digestibility, nitrogen balance, and microbial protein synthesis in sheep fed spineless-cactus silage and fresh spineless cactus

An experiment was carried out to compare the use of fresh cactus with cactus ensiled with and without a microbial inoculant in sheep diets by examining their feed intake, nutrient digestibility, nitrogen balance, and microbial protein synthesis and counting fecal enterobacteria. Twenty uncastrated mixed-breed sheep at approximately six months of age, with an average initial weight of 23.48 ± 2.40 kg, were used in the study. The animals were assigned to four treatments [fresh spineless cactus processed twice daily at the time of supply (FC2); fresh spineless cactus processed only once, in the morning, and supplied twice daily (FC1); spineless-cactus silage without inoculant (CS); and spineless-cactus silage with microbial inoculant (CSI)] in a completely randomized design with five replications per treatment. The experimental period was 21 days. The use of spineless cactus in the form of silage (CS and CSI) resulted in higher (P < 0.05) intakes of dry matter, organic matter, neutral detergent fiber, ether extract, non-fibrous carbohydrates, and total digestible nutrients; and higher digestibility coefficients of dry matter, organic matter, and total digestible nutrients. Lower counts of fecal enterobacteria were also observed with the ensiled cactus. By contrast, the diets did not influence (P> 0.05) nitrogen balance, microbial efficiency, urinary nitrogen losses, or fecal nitrogen losses. Regardless of inoculation, the ensiling of spineless cactus improves the sanitary quality of the diet, reducing the amount of enterobacteria in the cactus and resulting mainly in improved nutrient intake by sheep.

Effect of including functional oils in ovine diets on ruminal fermentation and performance

Abstract The objective of this study was to evaluate the effects that different levels of functional oil (FO) extracted from castor bean (CO) and cashew nut shell liquid (CNSL) have on nutrient intake and digestibility, rumen fermentation, N-use efficiency, and microbial protein synthesis in sheep. Four castrated male sheep of no defined breed, with rumen cannulation (49.1 kg ± 7 kg live weight), were used in a 4 × 4 Latin square. The animals were randomly assigned one of the following four treatments: control (0; without additives; and 2, 4, and 6 g/animal/day FO (commercial mix of CNSL and CO). The intake of digestible organic matter decreased linearly with the inclusion of FO. The treatments did not affect nutrient digestibility. Neither N use nor microbial protein synthesis were affected by the levels of FO in the diet. Rumen pH and parameters were similar among FO levels. The inclusion of a CNSL and CO mix in sheep diets can be considered a natural food supplement that decreases intake without negatively affecting nutrient fermentation and usage.

Apparent nutrient digestibility, nitrogen metabolism and microbial protein synthesis in sheep supplemented with different vegetable fats

The objective of the present study was to delineate the effect of different vegetable lipid supplements on apparent nutrients digestibility, nitrogen (N) metabolism and microbial protein synthesis in sheep reared under intensive conditions. Three Latxa sheep were used in a 3 × 3 Latin square design, with three 21-day periods (14-day adaptation and a 7-day sample collection each period), and were fed barley straw plus a concentrate mixture supplemented with (1) prilled palm fat (PALM), (2) cold-pressed rapeseed cake (CPRC) or (3) cold-pressed sunflower cake (CPSC). Organic matter intake did not differ among dietary treatments (P = 0.246). No significant differences were found between PALM and CPRC for apparent nutrients digestibility (P &amp;gt; 0.05), (N) balance (P &amp;gt; 0.05) or microbial protein synthesis (P &amp;gt; 0.05). The CPSC diet did not affect (N) intake (P = 0.481) and faecal losses (P = 0.753), but increased urinary N excretion (P = 0.030), and decreased N retention (P = 0.034), compared with PALM. Daily microbial protein synthesis, expressed as mmol of microbial N/day, was reduced by 18% with CPSC, compared with PALM (P = 0.001). Decreased microbial (N) supply was mainly due to a decline in the amount of substrate available for microbial protein synthesis due to a lower organic matter digestibility in CPSC-fed sheep. Overall, substituting palm fat with cold-pressed rapeseed cake in a high-concentrate fattening diet of sheep did not alter feed digestibility, efficiency of N utilisation or microbial protein synthesis. In contrast, replacing palm fat with cold-pressed sunflower cake reduced organic matter digestibility, increased (N) urinary losses and reduced microbial protein supply to the host animal.

Effect of Chinese herbal medicine on kinetics of plasma phenylalanine, tyrosine and whole body protein synthesis in sheep.

The aim of this study was to evaluate the effect of feeding decoction of a traditional nourishing Chinese herbal medicine formula on rates of plasma phenylalanine and tyrosine turnover and whole body protein synthesis in sheep. Ruminal fermentation characteristics and blood metabolites were also determined. Six sheep were subjected to either mixed hay (MH‐diet, as control) or MH‐diet supplemented with 2% of Chinese herbal medicine (mixture of Astragalus root, Angelica root, and Atractylodes rhizome; CHM‐diet) in a crossover design for each of 3‐week period. The isotope dilution of [2H5]phenylalanine and [2H2]tyrosine was performed as a primed‐continuous infusion to measure plasma phenylalanine and tyrosine kinetics. Concentrations of total volatile fatty acid, acetate, and propionate in the rumen tended to be higher (p < 0.10), and the pH value was lower (p = 0.04) for the CHM‐diet than the MH‐diet. Turnover rates of plasma phenylalanine and tyrosine tended to be higher (p < 0.10) for the CHM‐diet than the MH‐diet. Furthermore, whole body protein synthesis was greater (p = 0.04) for the CHM‐diet compared with the MH‐diet. The Chinese herbal medicine improved rumen fermentation and enhanced protein metabolism in sheep. Hence, it is suggested that the decoction of Chinese herbal medicine formula could be considered as a potential feed additive for ruminant production.

Effect of grinding process of steam-rolled barley grain on plasma glucose and leucine kinetics and protein synthesis in sheep

ABSTRACTAn isotope dilution method of [U-13C]glucose and [l-13C]leucine was simultaneously conducted to determine the effect of grinding process of steam-rolled barley grain on rates of plasma glucose and leucine turnover and whole-body protein synthesis (WBPS) in sheep. Six adult sheep were assigned to two dietary treatments and the experiment utilized a crossover design for two 21-day periods. The experimental diet was consisted of mixed hay and steam-rolled barley grain (1:1 ratio). Barley grain was treated either with or without grinding (GR diet and SR diet, respectively). Sheep were fed isoenergetically and isonitrogenously in both the treatments. The primed-continuous infusion method of [U-13C]glucose and [1-13C]leucine was simultaneously performed on day 21. The pH and ammonia concentrations in rumen fluid decreased (P < 0.05) and concentrations of total VFA, acetate, propionate and n-butyrate increased (P < 0.05) after feeding. Rates of plasma glucose and leucine turnover and WBPS did not differ between the dietary treatments. It is likely that grinding process of steam-rolled barley grain did not influence plasma glucose and leucine kinetics and WBPS in sheep fed the diets of mixed hay and barley grain at 1:1 ratio.

The Effect of Level of Feed Intake on Digestibility, Nitrogen Balance and Microbial Protein Synthesis in Sheep

The Effect of Level of Feed Intake on Digestibility, Nitrogen Balance and Microbial Protein Synthesis in Sheep

Chemical composition of alfalfa silage with waste date and its feeding effect on ruminal fermentation characteristics and microbial protein synthesis in sheep

This study was conducted to evaluate the effect of feeding ensiled alfalfa with waste date on ruminal fermentation characteristics, microbial protein synthesis, protozoa population and blood parameters in sheep. Eight rams were used in a 2×2 change over design. Each experimental period consisted of 21days including 16days for adaptation and 5days for sampling. For ensiling, fresh alfalfa (Medicago sativa L.) with different levels of waste date (Phoenix dactylifera L.) were mixed together and ensiled in 100-l containers for 45days. Chemical composition of silages such as dry matter (DM), crude protein, NH3 -N, organic matter, NDF, ADF and pH were determined. Then, it was used as 30% (DM basis) in diets. The experimental diets were as follows: (i) control (diet containing alfalfa silage without waste date), (ii) diet containing alfalfa silage with 5g waste date/95g DM, (iii) diet containing alfalfa silage with 10g waste date/90g DM, and (iv) diet containing alfalfa silage with 15g waste date/85g DM. The results of this experiment showed that adding waste date to alfalfa during ensiling, improved silage quality, DM and energy level. Total protozoa population and all of holotrich, cellulolytic and entodinia in rumen fluid were increased linearly by increasing the level of waste date. Nitrogen (N) intake, urinary N excretion and nitrogen retention were affected by dietary treatments. Also, allantoin, uric acid, total purine derivatives, microbial protein synthesis, cholesterol level and blood urea nitrogen were significantly different. In conclusion, direct ensilage of alfalfa can be attained by mixing 15g waste date/85g DM and positive associative effects such as increased metabolizable energy (ME) and silage quality occurred.

EFFECT OF SYNCHRONIZATION OF CARBOHYDRATE AND PROTEIN SUPPLY IN THE SUGARCANE BAGASSE BASED DIET ON MICROBIAL PROTEIN SYNTHESIS IN SHEEP

The experimental research was conducted to clarify the effect of synchronization of ruminal carbohydrate and protein releases from sugarcane bagasse based diet (SBBD) on microbial protein synthesis in sheep. The first experiment was the formulation of three SBBD with similar nutrient content but differed in synchronization indexes (namely 0.36; 0.50 and 0.63). The in sacco nutrient degradability coefficient was used to calculate the synchronization index of each feedstuff. The second experiment was determination of post feeding ruminal pH, ruminal concentrations of total volatile fatty acids (TVFA) and ammonia nitrogen (NH3-N), and blood urea nitrogen (BUN) level in sheep fed on experimental SBBD. The third experiment was determination of feed digestibility and estimation of microbial nitrogen synthesis (MNP) on the basis of excreted urinary allantoin. The alteration of dietary synchronization index did not change nutrient intake, but the digestibilities of DM, OM and CP were increased (P&lt;0.05). The post feeding ruminal pH was decreased (P&lt;0.05) but concentrations of post feeding ruminal TVFA and NH3-N, and level of BUN were increased (P&lt;0.05) by the treatment of dietary synchronization index. The treatment of dietary synchronization index improved MNP (P&lt;0.05), although dietary synchronization index at 0.63 lowered the MNP (P&lt;0.05).

Ruminal fermentation, nutrient digestibility and microbial protein synthesis in sheep fed diets with different levels of date pulp

Four ruminally cannulated mature Kermani sheep (50 ± 2.3 kg and 40 ± 2.1 months old) were used in a 4 × 4 Latin square design to determine the effects of diets with different levels of date pulp (DP) on ruminal fermentation, nutrient digestibility and microbial protein synthesis. DP was replaced for wheat bran in diets at no DP (0 DP), 7 (7 DP), 14 (14 DP) and 21% (21 DP) of diet dry matter (DM) and were fed twice daily (0800 hours and 1800 hours). In this study, increasing the amount of DP in diets of sheep did not affect DM intake and apparent digestibility of nutrient (P &gt; 0.05). Inclusion of DP in diets increased ruminal pH linearly (P &lt; 0.05), but did not influence total volatile fatty acids and molar proportion of individual volatile fatty acids (P &gt; 0.05). Ruminal ammonia nitrogen concentration (6.04 vs 10.13 mmol/L), and blood urea nitrogen (8.59 vs 13.10 mg/dL) were affected by diets (P &lt; 0.05). Moreover, urinary nitrogen excretion was higher (P &lt; 0.05) for Control diet (no DP) than the 21 DP diet. In this study, urinary excretion of purine derivatives and microbial protein synthesis were affected by experimental diets (P &lt; 0.05). In conclusion, this study showed that DP at 14% can be used as an alternative feed resource in sheep nutrition especially in semiarid areas.

Effect of increasing levels of wasted date palm on digestion, rumen fermentation and microbial protein synthesis in sheep.

This study was conducted to evaluate the effects of increasing levels of wasted date (WD) in sheep (initial body weight 50±2.3kg) diets on apparent diet digestibility, rumen fermentation and microbial protein synthesis. The experimental diets contained 0 (0 WD), 9% (9 WD), 18% (18 WD) or 27% (27 WD) of wasted dates. These diets were evaluated through a 4×4 Latin square design with four 28-day periods. Sheep were individually housed in metabolic cages and were fed diets adlibitum. To keep the diets isoenergetic and isonitrogenous, increasing partial replacement of WD for barley grain was used with increasing levels of soya bean meal. Increasing the amount of WD in diets of sheep did not influence (p>0.05) diet intake and digestibility of nutrients. Inclusion of WD in diets of sheep did not affect (p>0.05) ruminal pH but decreased (p<0.05) NH3 -N concentration and blood urea nitrogen. Also there was no effect (p>0.05) of the WD provision on N intake and faecal N loss of experimental animals, but urinary nitrogen excretion and retained nitrogen were affected (p<0.05) by dietary treatments. Purine derivatives and microbial protein synthesis increased (p<0.05) linearly with the level of WD in the diet. In conclusion, the increase in microbial protein synthesis and concomitant reduction in ruminal NH3 -N concentration and blood urea nitrogen in response to wasted date supply suggest improved efficiency of ruminal nitrogen metabolism without adverse effects on fermentation characteristics and animal performance.

Interaction effects of degradable nitrogen sources and straw treatment on rumen parameters and microbial protein synthesis in sheep

In this study, the effects of 2 rumen degradable nitrogen, N, source (urea vs. casein) were investigated on rumen degradability, ammonia concentration, dilution rate, microbial protein synthesis (MPS) and MPS efficiency (EMPS) in sheep fed diet based on untreated straw (US) or treated straw (TS). Four rumen fistulated sheep were assigned to 1 of the 4 treatments: (i) US with urea (USU); (ii) US with casein (USC); (iii) TS with urea (TSU); and (iv) TS with casein (TSC), according to a 4 × 4 Latin square design. Barley straw was treated with 4.1% sodium hydroxide (w/ w DM basis; pH 11.5) followed by 2% hydrogen peroxide. The treated straw was packed in 220 l drums and kept for 6 weeks. Compared to US diets, feeding the TS diets enhanced ruminal fiber degradability (62.3 vs 46.3%), total tract organic matter (OM) digestibility (59.4 vs 53.8%), OM intake (768 vs 546 g/d), dilution rate (0.082 vs 0.056/h), and MPS (45.7 vs 29.7 g/d), but it had no effect on EMPS. Rumen fiber degradability but not the DM one of only TS enhanced with casein supplementation as compared to urea supplementation. No interaction was found between supplemented nitrogen sources and straw type. It is concluded that substitution of US with TS increased intake, digestibility and MPS when supplemented with either urea or casein as nitrogen source. However, fiber degradability was improved with casein supplementation.

Effect of feeding garlic leaf on microbial nitrogen supply, kinetics of plasma phenylalanine, tyrosine and protein synthesis in sheep

The objective of the present study was to assess the feeding effects of garlic leaf on microbial N supply (MNS), turnover rates of plasma phenylalanine (PheTR) and tyrosine (TyrTR) and whole body protein synthesis (WBPS) in sheep. The sheep were fed either mixed hay (Hay-diet, as control) or hay plus garlic leaf diet (GL-diet, at a ratio of 9:1) in a crossover design each for a 21 day period. The isotope dilution method using [(2) H5 ]Phe and [(2) H2 ]Tyr was performed on the 21st day of each dietary treatment. Nitrogen intake remained similar between the diets and N absorption and N digestibility were higher (P<0.05) in the GL-diet than Hay-diet. Total purine derivatives excretion and MNS were greater (P<0.05) in the GL-diet than the Hay-diet. Plasma PheTR tended to be higher (P=0.06) during GL feeding and TyrTR did not differ between the diets. Further, WBPS tended to be greater (P=0.05) for the GL-diet compared with the Hay-diet. Hence, the present results suggest that garlic leaf may have positive effects on N metabolism by influencing MNS in sheep and could be used as a potential ruminant feed in the future.

Digestion and microbial protein synthesis in sheep as affected by exogenous fibrolytic enzymes

The aim of the study was to determine the effect of an exogenous fibrolytic enzyme (EFE) on the ruminal disappearance of dry matter (DM), neutral detergent fibre (NDF), crude protein (CP) and on the microbial protein synthesis (MPS) in sheep of a milled substrate consisting of a 50 : 50 mixture of lucerne hay (LH) and wheat straw (WS). Four cannulated D&#246;hne-Merino sheep were randomly assigned to two groups in a 2 x 2 cross-over experiment. Additional to the in situ study, the effects of an exogenous fibrolytic enzyme (EFE) on the in vitro gas production (GP) and ANKOM digestion systems on the mixture of milled LH and WS were determined. The substrate was pre-treated with distilled water (control) or EFE (treatment) 12 hours prior to incubation to allow interaction between the substrate and enzyme. Adding EFE significantly improved the in vitro cumulative gas production (GP), but it did not affect the in vitro MPS measured as purine derivates of the GP residues. The enzyme significantly increased the in vitro DM and NDF disappearances after 36 hours. However, the in situ disappearances of DM, NDF and CP of the roughage mixture were not affected by the EFE. Further, the in situ MPS was increased significantly with the EFE treatment of the mixed substrate. It is concluded that the improved ruminal digestion of DM, NDF and CP is not only due to direct enzyme hydrolysis, but also due to the improvement of MPS.Keywords: Fibre digestion, in vitro and in situ digestion, ruminants

Supplementation with non-fibrous carbohydrates reduced fiber digestibility and did not improve microbial protein synthesis in sheep fed fresh forage of two nutritive values

To determine whether non-fibrous carbohydrate (NFC) supplementation improves fiber digestibility and microbial protein synthesis, 18 Corriedale ewes with a fixed intake level (40 g dry matter (DM)/kg BW0.75) were assigned to three (n = 6) diets: F = 100% fresh temperate forage, FG = 70% forage + 30% barley grain and FGM = 70% forage + 15% barley grain + 15% molasses-based product (MBP, Kalori 3000). Two experimental periods were carried out, with late (P1) and early (P2) vegetative stage forage. For P2, ewes were fitted with ruminal catheters. Forage was distributed at 0900 h, 1300 h, 1800 h and 2300 h, and supplement added at 0900 h and 1800 h meals. Digestibility of the different components of the diets, retained N and rumen microbial protein synthesis were determined. At the end of P2, ruminal pH and N-NH3 concentration were determined hourly for 24 h. Supplementation increased digestibility of DM (P < 0.001) and organic matter (OM; P < 0.001) and reduced NDF digestibility (P = 0.043) in both periods, with greater values in P2 (P = 0.008) for the three diets. Daily mean ruminal pH differed (P < 0.05) among treatments: 6.33 (F), 6.15 (FG) and 6.51 (FGM). The high pH in FGM was attributed to Ca(OH)2 in MBP. Therefore, the decreased fiber digestibility in supplemented diets could not be attributed to pH changes. The mean ruminal concentration of N-NH3 was 18.0 mg/dl, without differences among treatments or sampling hours. Microbial protein synthesis was greater in P2 (8.0 g/day) than in P1 (6.1 g/day; P = 0.006), but treatments did not enhance this parameter. The efficiency of protein synthesis tended to be lower in supplemented groups (16.4, 13.9 and 13.4 in P1, and 20.8, 16.7 and 16.2 g N/kg digestible OM ingested in P2, for F, FG and FGM, respectively; P = 0.07) without differences between supplements. The same tendency was observed for retained N: 2.55, 1.38 and 1.98 in P1, and 2.28, 1.23 and 1.10 g/day in P2, for F, FG and FGM, respectively; P = 0.05). The efficiency of microbial protein synthesis was greater in P2 (P = 0.007). In conclusion, addition of feeds containing NFCs to fresh temperate forage reduced the digestibility of cell walls and did not improve microbial protein synthesis or its efficiency. An increase in these parameters was associated to the early phenological stage of the forage.

Effect of grinding size and sunflower oil addition on intake, digestibility, rumen function and microbial protein synthesis in sheep fed a dry total mixed ration

An experiment was carried out in which the effect of grinding a dry total mixed ration, based on barley straw, through 6 or 10 mm sieves on intake, digestibility, rumen function and microbial protein synthesis in sheep was assessed. The effect of including 1% sunflower oil as binder was also explored. None of the variables studied was affected by grinding size, hence the 10 mm sieve was recommended due to its lower cost in terms of energy consumed. On the contrary, addition of 1% sunflower oil significantly increased ammonia concentration in the rumen (83 vs. 161 mg L–1; p = 0.002), potential degradabilities (as proportion) of dry matter (0.65 vs. 0.75; p = 0.0037), organic matter (0.68 vs. 0.75; p = 0.0005) and crude protein (0.78 vs. 0.90; p = 0.0004), and fractional rate of degradation (0.066 vs. 0.080 h–1; p = 0.046) and effective degradability, as proportion (0.63 vs. 0.73; p = 0.010), of this latter. Oil addition (1%) is then recommended as binder, although a more economical option than sunflower oil should be explored due to its high cost.

Effects of urea and soybean meal supplementation on rates of plasma leucine turnover and protein synthesis in sheep fed concentrate-based diets

The isotope dilution method of [1-13C]leucine (Leu) and open-circuit calorimetry were used to determine the effects of urea and soybean meal (SBM) supplementation on rates of plasma Leu turnover and whole body protein synthesis (WBPS) in sheep fed concentrate-based diets. The experiment was performed in a replicated 3×3 Latin square design. The control diet (Control diet) consisted of timothy hay and ground corn. The urea supplemented diet (Urea diet) was supplemented with 3.1% urea of the Control diet. The SBM diet was similar to nitrogen and ME contents to the Urea diet by replacing 40% ground corn of the Control diet to the SBM. Plasma urea concentration was higher (P<0.05) for the SBM and Urea diets compared with the Control diet, but plasma ammonia concentration remained similar for all diets. Plasma free amino acid concentration also remained unchanged between the diets, except for plasma glycine concentration. Plasma Leu turnover rate and WBPS did not differ between the diets, but they were numerically higher for the SBM diet compared with the Control and Urea diets. These results suggest that in sheep, urea and SBM supplementation influence little on plasma Leu and protein metabolism, when concentrate-based diets are given.

Selecting browse plants to supplement cassava peel-based diet for peri-urban small ruminants

Cassava ( Manihot esculanta) peel is routinely fed to ruminants in Ghana and most parts of Africa, but the low protein content and lack of suitable protein supplements limits its full exploitation in small ruminant production systems. This study assessed the suitability (degradation characteristics and synchrony between nitrogen release and organic matter degradation) of the leaves of three browse plants, chaya ( Cnidoscolus aconitifolius), ficus ( Ficus exasperata), and terminalia ( Terminalia catappa), as supplements for sheep fed a cassava peel-based diet. Four ruminally fistulated Djallonké wethers were used in a randomized complete block design experiment to determine ruminal disappearance of dry matter (DM), organic matter (OM) and nitrogen (N) from the three leaves and from cassava peels. For chaya, ficus and terminalia, OM content was 93.1%, 83.8% and 90.3% ( P < 0.05), respectively, whereas N was 3.4%, 3.1% and 1.7% ( P < 0.05, DM basis). The OM and N content in cassava peel was 95.3% and 1.0%, respectively. Ruminal DM disappearance of chaya, ficus, terminalia and cassava peel after 24 h of incubation was 79.0%, 36.4%, 48.0%, and 43.0% ( P < 0.05), respectively. The ratio of N released from chaya leaves to OM from cassava peel was 1:16 or lower during 24 h ruminal incubation, compared to 1:31 during the first 8 h and 1:25 after 12 h of incubation of ficus leaves. The ratio for terminalia leaves from 4 to 24 h of incubation ranged between 1:51 and 1:63. The high N content and ideal synchronous release of N and OM ratio of 1:33 (N:OM) made ficus leaves the most suitable supplement among the three browse leaves, with the potential to supply adequate N to optimize ruminal microbial protein synthesis in sheep on a cassava peel-based diet.

Effects of dietary energy intake and cold exposure on kinetics of plasma phenylalanine, tyrosine and protein synthesis in sheep

An isotope dilution method of [2H5]phenylalanine (Phe) and [2H2]tyrosine (Tyr) was used to determine the effects of metabolisable energy (ME) intake and cold exposure on plasma Phe and Tyr turnover rates in sheep. Whole body protein synthesis (WBPS) was calculated with the [2H5]Phe model. Eight adult sheep were assigned to two dietary treatments receiving the same amount of crude protein and either 515 or 828 kJ · kg BW−0.75 · d−1 of ME (Me-ME diet and Hi-ME diet, respectively) with a crossover design for two 28 d periods. The sheep were exposed from a thermoneutral environment (23 ± 1°C) to a cold environment (2 ± 1 to 4 ± 1°C) for 6 d for each dietary treatment. The primed-continuous infusion method of isotope dilution was conducted in both environmental temperatures. Plasma Phe turnover rate (PheTR) tended to be greater and plasma Tyr turnover rate (TyrTR) was greater (p = 0.03) for the Hi-ME diet compared with the Me-ME diet. Plasma PheTR increased (p = 0.04) and plasma TyrTR tended to increase during cold exposure. Whole body protein synthesis tended to be greater for the Hi-ME diet compared with the Me-ME diet and increased (p = 0.03) during cold exposure compared to the thermoneutral environment, but no interaction was detected. It was concluded that in sheep, plasma PheTR and WBPS (as determined by the [2H5]Phe model) tended to be influenced by and plasma TyrTR was influenced by ME intake. Further, plasma PheTR and WBPS increased and plasma TyrTR tended to increase during cold exposure.

Purine derivative excretion and microbial protein synthesis in sheep fed a roughage-based diet supplemented with or without grass silage

In a 3 x 3 Latin square design experiment, urinary excretions of purine derivatives (allantoin N, Uric acid N, Xanthine + Hypoxanthine N) were measured and used to estimate microbial N yield in 9 sheep fed roughage- based diet supplemented with 0, 150 and 300g DM grass silage respectively.&nbsp; Daily urinary excretions of allantoin N, uric acid N, xanthine + hypoxanthine were 3.66, 3.77,4.51, 0.95,1.18,1.24; 1.01,1.21 and 1.34 mmol d-1 for sheep fed roughage-based diet and supplemented with 0,150 and 300g DM silage respectively. Allantoin N, Uric acid N and Xanthine + Hypoxanthine N excretion increased significantly (P&lt;0.01) with increasing amount of silage. Dry matter intake which increased with level of supplementation significantly (P&lt; 0.01) influenced estimated microbial protein yield, which ranged from 4.86 to 6.14g N d-1. The efficiency of conversion of dietary N into microbial N which ranged from 48.17 to 57.22 g N/100g DN was highly significant (P&lt;0.01) as the level of supplementation increased. Microbial N yield per kg of OM fermented (gN/kg DOMR) increased linearly. The results indicate that the amount of microbial N biomass made available to the host animal per unit of feed fermented could be influenced by feed type, level of intake and size of animal. The results also showed that allantoin constituted the highest proportion of purine derivatives excreted. &nbsp;Key Words: Microbial protein, purines, sheep, roughage, silage