The effects of condensed tannins from Desmodium intortum and Calliandra calothyrsus on protein and carbohydrate digestion in sheep and goats

Could natural phytochemicals be used to reduce nitrogen excretion and excreta-derived N2O emissions from ruminants?

Ruminants play a critical role in our food system by converting plant biomass that humans cannot or choose not to consume into edible high-quality food. However, ruminant excreta is a significant source of nitrous oxide (N2O), a potent greenhouse gas with a long-term global warming potential 298 times that of carbon dioxide. Natural phytochemicals or forages containing phytochemicals have shown the potential to improve the efficiency of nitrogen (N) utilization and decrease N2O emissions from the excreta of ruminants. Dietary inclusion of tannins can shift more of the excreted N to the feces, alter the urinary N composition and consequently reduce N2O emissions from excreta. Essential oils or saponins could inhibit rumen ammonia production and decrease urinary N excretion. In grazed pastures, large amounts of glucosinolates or aucubin can be introduced into pasture soils when animals consume plants rich in these compounds and then excrete them or their metabolites in the urine or feces. If inhibitory compounds are excreted in the urine, they would be directly applied to the urine patch to reduce nitrification and subsequent N2O emissions. The phytochemicals' role in sustainable ruminant production is undeniable, but much uncertainty remains. Inconsistency, transient effects, and adverse effects limit the effectiveness of these phytochemicals for reducing N losses. In this review, we will identify some current phytochemicals found in feed that have the potential to manipulate ruminant N excretion or mitigate N2O production and deliberate the challenges and opportunities associated with using phytochemicals or forages rich in phytochemicals as dietary strategies for reducing N excretion and excreta-derived N2O emissions.

Can phytogenic additives replace monensin sodium in beef cattle feeding?

Monensin sodium is one of the most common ionophores used in livestock feeding; however, ionophores are condemned by organized consumer groups. Bioactive compounds from plants found in the seasonally dry tropical forest have similar mechanisms of action as ionophores. The aim was to investigate the effects of replacing monensin sodium with phytogenic additives on the nutritional efficiency of beef cattle. Five 14-month-old Nellore bulls (average body weight 452.68 ± 42.60 kg) were used in the study. The experiment was designed as a 5 × 5 Latin Square (five treatments and five 22-day experimental periods). Within each period, 15 days were used for adaptation of animals to experimental conditions and 7 days for data collection. Bulls were fed a control diet (without additives), monensin (a diet containing monensin sodium 40% as a synthetic additive), and three diets containing phytogenic additives prepared from Anadenanthera macrocarpa (Benth) Brenan, Mimosa tenuiflora (Willd) Poiret, or Prosopis juliflora (Sw.) DC. Nutritional efficiency was assessed through feed intake, nutrient digestibility, feeding behavior, and hematological parameters. Monensin and phytogenic additives did not influence (P > 0.05) feeding behavior or hematological parameters, but the nutrient intake was highest for bulls supplemented phytogenic additives (P < 0.05). Monensin supplementation did not influence (P > 0.05) feed intake. The phytogenic additives and monensin sodium increased (P < 0.05) the nutrient digestibility. Therefore, the phytogenic additives from P. juliflora, A. macrocarpa, and M. tenuiflora can be recommended to enhance the nutritional efficiency of confined Nellore cattle.

Feeding tannins to dairy cows in different seasons improves the oxidative status of blood plasma and the antioxidant capacity of cheese

The aim of the present study was to assess the dietary supplementation of tannins to grazing dairy cows in 2 seasons characterized by a good quality pasture (spring) or a poor-quality pasture (summer). The effects of dietary tannins were assessed on plasma antioxidant status and cytokines profile and on the antioxidant properties of cheese and cheese in vitro digestates. Fourteen lactating dairy cows were divided into 2 homogeneous groups (n = 7): a control group (CON), and an experimental group (TAN) receiving 150 g/head per day of tannins supplementation. The experiment was performed twice, in spring and in summer. The animals were free to graze on spontaneous pasture (spring) or on dry stubble (summer). Blood was sampled at the beginning (d 0), at the midpoint (d 11), and at the end (d 22) of the trial. Individual cheese was produced before the beginning (d -1) and at the end (d 22) of the trial from the milk collected from each cow. On blood plasma, the reactive oxygen metabolites (ROM), biological antioxidant potential (BAP), nonesterified fatty acids quantification, and cytokines profile in terms of IL-10, IL-8, IL-1β, and IFN-γ were determined. Data on ROM demonstrated that tannins supplementation lowered oxidative stress both in spring and in summer. Accordingly, TAN diet increased BAP levels compared with the CON during summer trial. Thus, feeding tannins resulted in lower ratio between ROM and BAP (oxidative stress index) in both spring and summer. Cytokines' profile showed lower IL-1β values in TAN group at d 22 during spring season, with a concomitant higher IL-10 level, during summer season. Moreover, TAN group had a lower level of IFN-γ in plasma than CON group, both in spring and in summer. On cheese samples, the in vitro digestion was performed and on cheese and cheese digestates (gastric and intestinal digestate) the free radical scavenging antioxidant activity was evaluated. The intestinal digestate fraction registered the highest antioxidant activity compared with cheese and gastric digestate, in both spring and summer seasons. Furthermore, an improvement of the antioxidant property of cheese and cheese digestates was found. Present data demonstrated that tannins supplementation contributed to reduce the oxidative stress of lactating dairy cows and showed an increase of anti-inflammatory cytokines ratio.

Effects of replacing Brachiaria hay with either Desmodium intortum or dairy concentrate on animal performance and enteric methane emissions of low-yielding dairy cows

In Africa, cattle are often fed low quality tropical roughages resulting in low-yielding animals with high methane (CH4) emission intensity (EI, g CH4/per unit of product). Supplementation with protein is known to improve the nutritive value of the otherwise low-quality diets. However, animal nutrition studies in East Africa that are accompanied by CH4 emission measurements are lacking. Thus, an animal experiment was conducted to quantify the effect of supplementing cattle fed mainly on low-quality Urochloa brizantha hay (control diet; CON; crude protein (CP) = 7.4%) or supplemented with either a tannin-rich leguminous fodder, Desmodium intortum hay (DES) or a commercial dairy concentrate (CUBES) on voluntary dry matter intake (DMI), nutrient apparent total tract digestibility, nitrogen (N) retention, enteric CH4 production and animal performance (milk and average daily gain). Twelve mid-lactating crossbred (Friesian × Boran) cows (initial liveweight = 335 kg) were used in a 3×3 (Period × Diet) Latin square design with each period running for four weeks. Compared to CON, DES decreased nutrient (DM, OM, CP) intake, apparent total tract digestibility and daily milk yield. In contrast, CUBES increased nutrient intake and animal performance compared to CON, while nutrients’ apparent total tract digestibility was not different, except for CP digestibility that increased. Compared to CON, DES and CUBES improved overall N retention by the animals as a proportion of N intake. The DES diet compared with CON and CUBES, shifted the proportion of N excretion via urine to the fecal route, likely because of its tannin content. Both DES and CUBES, compared to CON, reduced methane yield (MY, g CH4/kg DMI) by 15% and 9%, respectively. The DES diet reduced absolute enteric CH4 emissions by 26% while CUBES increased emissions by 11% compared to CON. Based on the present findings, high supplementation levels (&gt;50%) of Desmodium intortum hay is not recommended especially when the basal diet is low in CP content. Supplementation with lower levels of better managed Desmodium intortum forage however, need to be investigated to establish optimal inclusion levels that will improve animal productivity and reduce environmental impact of livestock in smallholder tropical contexts.

The Fate of Tannins from Birdsfoot Trefoil and Their Effect on the Nitrogen Balance in Growing Lambs Fed Diets Varying in Protein Level

Simple Summary

Feeding forage legumes containing condensed tannins (CT) to ruminants has the potential to reduce urinary nitrogen (N) excretion, which is considered a significant contributor to environmental pollution. However, there are also indications that CT in the diet can reduce the feed intake. Furthermore, the fate of CT during digestion is still unclear. In the present study, the effect of CT from birdsfoot trefoil (BT) on the N excretion pathway and the CT excretion of lambs fed diets with different dietary crude protein (CP) levels were investigated. Regardless of the crude protein content of the diet, the results show that the CT-containing rations were eaten less frequently. Nitrogen excretion via urine decreased with the feeding of CT, but only in absolute terms and not in relation to the N intake. The CT balance indicates that not all CT that are ingested are also excreted. It seems that the CT change their structure when passing through the digestive tract.

Abstract

Two experimental periods were employed to investigate the fate of ingested CT from BT and their effects on the intake, digestibility, and N balance in lambs fed diets differing in CP levels. In period 1, 24 lambs were fed a basal diet either treated with polyethylene glycol (PEG+) to deactivate CT or without polyethylene glycol (PEG−). In period 2, the same lambs were used in a 2 × 2 factorial design and fed either the basal diet (BP) or a high protein diet (HP), again treated with or without PEG. In both experimental periods, feeding lambs diets without PEG caused a reduction in the dry matter (DM) intake and an increase in the DM digestibility. Urinary and total N excretion decreased in lambs fed diets without PEG, but only in absolute terms and not in relation to the N intake. The total N intake, total N excretion, and body N retention were higher with a higher dietary CP level. Related to the CT intake, less soluble and protein-bound CT were excreted by lambs fed diets without PEG, and more protein-bound and fiber-bound CT were excreted by lambs fed BP diets. Regardless of the PEG treatment and CP level, not all CT that are ingested are also excreted. The effect of PEG treatment on the N excretion pathway was independent of the CP level.

Effects of dietary grapeseed extract on performance, energy and nitrogen balance as well as methane and nitrogen losses of lambs and goat kids

The influence of phenol-rich dietary grapeseed extract on performance, energy and N balance and methane production was determined in sixteen lambs and thirteen goat kids (body weight 20·5 and 19·0 kg, 2 months of age, day 1 of study). Half of the animals received a concentrate containing grapeseed extract, and the others received concentrate without grapeseed extract (total extractable phenols analysed 27 v. 9 g/kg dietary DM; concentrate and hay 1:1). Diets were fed for 7 weeks with 1 week for determining intake, excretion and gaseous exchange in metabolism crates and respiration chambers. Overall, there was an adverse effect of the phenolic diet on apparent N digestibility and body N retention. Faecal N loss as proportion of N intake increased while urinary N loss declined. Relative to N intake, total N excretion was higher and body N retention lower in goat kids than lambs. Diets and animal species had no effect on methane emissions. The saliva of the goat kids had a higher binding capacity for condensed tannins (CT). Goat kids on the phenolic diet had higher CT concentrations in faeces and excreted more CT compared with the lambs (interaction species × diet P < 0·001). The lambs had overall higher (P < 0·001) urinary phenol concentrations than the goat kids (2·19 v. 1·48 g/l). The negative effect on body N retention and lack of effect on methane emissions make the use of the extract in the dosage applied not appealing. Species differences need to be considered in future studies.

Effects of Feeding Multinutrient Blocks Including Avocado Pulp and Peels to Dairy Goats on Feed Intake and Milk Yield and Composition

Simple Summary

The high and volatile prices of conventional ingredients for animal feeding has directed the attention of ruminant nutritionists toward local alternative resources such as agroindustrial by-products and fruits wastes. The inclusion of these resources in the diet might contribute to reducing feeding costs and environmental issues associated with both livestock production and by-products and wastes accumulation might be prevented. The global production and consumption of avocado have risen sharply in recent years, partly due to the recognition of its health-promoting potential in humans. The increased consumption of avocado and its derivatives is producing great amounts of wastes and by-products that might be reutilized in ruminant feeding. Our hypothesis was that avocado wastes (a mixture of pulp and peels) could be included in multinutrient blocks for dairy goats and improve the quality of the milk fatty acid profile without negatively affecting milk yield. However, the intake of multinutrient blocks containing 14.8% avocado wastes was low probably due to avocado lipids oxidation and rancidity. No changes were observed in milk production, but feeding blocks with avocado wastes increased milk fat content with only subtle changes in the fatty acid profile of fat milk.

Abstract

Twelve Murciano-Granadina dairy goats were divided into two homogeneous groups, which were fed either a control diet composed of 40% alfalfa hay and 60% concentrate or a diet based on 40% alfalfa hay, 40% concentrate and 20% multinutrient blocks, including 14.8% avocado pulp and peels (APP). Total dry matter (DM) intake was similar (p = 0.709) for both diets, but APP-fed goats had lower (p = 0.024) concentrate intake and tended (p = 0.063) to have lower fat intake compared with those fed the control diet. The average intake of blocks was low (66.4 g DM/d), which was attributed to avocado lipids oxidation and rancidity. Neither milk yield (p = 0,921) nor the efficiency of energy and nitrogen use were affected (p = 0.909 and 0. 840, respectively) by the diet, but milk fat tended to be greater (p = 0.057) in the APP-fed goats compared with the animals fed the control diet. Other milk components were similar (p ≥ 0.110) for both diets, and only subtle changes in the milk fatty acid profile were observed. In summary, the intake of blocks containing avocado wastes by dairy goats was low probably due to avocado lipids oxidation causing off-flavors and reduced palatability.

Influence of elevated protein and tannin-rich peanut skin supplementation on growth performance, blood metabolites, carcass traits and immune-related gene expression of grazing meat goats

The aim of the present study was to define whether elevated rumen-undegradable protein (RUP) and tannin-rich peanut skin (PS) supplementation would affect animal growth performance, average daily gain (ADG), blood metabolites, carcass traits associated with lipogenic and immune-related gene expressions in meat goats grazing winter wheat (WW). Thirty-six Kiko-crossbreed male goats at approximately 6 months of age were blocked by body weight (BW; 25.6 ± 1.1 kg) and randomly assigned to one of the four treatments with two replicates based on a 2 × 2 factorial design. Diets contained PS replacing alfalfa meal (ALM), without or with RUP supplementation. Both PS and ALM were incorporated into grain mix portion of the diet and pelletized, with remaining diets fed ad libitum of WW forage for a period of 51 days. Lipogenic genes examined included SCD, ACLY, YWHAZ, PPIA and FABP4, while immune-related genes examined included ACTB (as a control gene), H3F3A, PPIA, IRF3, STAT2, HERC3 and IFIT3 antibody genes. The meat goats on PS-pellet-supplemented group with or without RUP supplementation grew 38.5% faster ADG (p < .001) when compared to control-supplemented group. When goats received PS diet, empty body weight, hot carcass, cold carcass, shoulder, hind shank, rack, loin and fat thickness were greater (p < .05) than control diet. Animals on PS-pellet had higher ACLY, YWHAZ, PPIA and FABP4 gene expression (p < .05) when compared to ALM-pellet control, with RUP by PS-pellet interactions (p < .01). Goats receiving additional RUP supplementation had increased (p < .05) STAT2 gene expression, whereas goats receiving PS-pellet supplementation showed increased STAT2 (p < .05) and a tendency to increase IRF3 (p = .07) gene expressions. In conclusion, the addition of PS-pellet or RUP supplementation has the potential to improve ADG and altered selected lipogenic and immune-related gene expressions.

Condensed Tannin Changes along the Digestive Tract in Lambs Fed with Sainfoin Pellets or Hazelnut Skins

The variable anthelmintic efficacy of condensed tannins (CT) against gastrointestinal nematodes may depend on CT concentration, composition, or fate along the digestive tract. We analyzed CT concentration and composition by acetone-HCl-butanol and thiolysis coupled to HPLC-MS in digesta and feces of lambs. Lambs had been infected with Haemonchus contortus and Trichostrongylus colubriformis and received sainfoin pellets and hazelnut skins of contrasting prodelphinidin/procyanidin ratios. The digesta and feces had lower CT concentrations than the original feeds but similar concentration patterns across the digestive compartments. The changes in assayable CT concentrations between rumen, abomasum, and small intestine may be due to complex formation between CT and other dietary components. However, the large CT disappearance (61-85%) from feed to feces could also indicate that CT may have been structurally modified, degraded, or absorbed during digestion. Interestingly, there were no changes in the structural features of assayable CT in the digesta.

In vitro microbial protein synthesis, ruminal degradation and post-ruminal digestibility of crude protein of dairy rations containing Quebracho tannin extract

This study evaluated the effects of Quebracho tannin extract (QTE) on in vitro ruminal fermentation, chemical composition of rumen microbes, ruminal degradation and intestinal digestibility of crude protein (iCPd). Three treatments were tested, the control (basal diet without QTE), the basal diet with 15 g QTE/kg dry matter (DM) and the basal diet with 30 g QTE/kg DM. The basal diet contained (g/kg DM): 339 grass silage, 317 maize silage and 344 concentrate. In vitro gas production kinetic was determined using the Hohenheim gas test (Experiment 1). The Ankom RF technique, a batch system with automatic gas pressure recordings, was used to determine in vitro production of short-chain fatty acids (SCFA) and ammonia-nitrogen concentration (NH₃ -N), as well as nitrogen and purine bases content in liquid-associated microbes (LAM) and in a residue of undegraded feed and solid-associated microbes (Feed+SAM) (Experiment 2). Ruminal degradation and iCPd were determined using the nylon bag technique and the mobile nylon bag technique, respectively (Experiment 3). Gas production (Experiment 1), total SCFA and NH₃ -N (Experiment 2) decreased with increasing QTE levels. Microbial mass and composition of LAM were not affected by QTE, but total mass of Feed+SAM linearly increased, likely due to decreased substrate degradation with increasing QTE levels. The total amount of N in microbial mass and undegraded feed after the in vitro incubation increased with increasing QTE levels, suggesting a potential greater N flow from the rumen to the duodenum. In contrast to in vivo studies with the same QTE, no effects were detected on ruminal effective degradability and iCPd, when using the nylon bag techniques. Based on the in vitro procedures, QTE increased the supply of N post-rumen; however, some evidence of a decreased fibre degradation were also observed. Therefore, the benefit of adding QTE to diets of cattle is still questionable.

Manipulation of ruminal fermentation and methane production by dietary saponins and tannins from mangosteen peel and soapberry fruit

Four fistulated Holstein Friesian heifers were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement. The main factors were two roughage-to-concentrate ratios (R:C, 70:30 and 30:70) and two supplementation levels of soapberry fruit-mangosteen peel (SM) pellets (0 and 4% tannins-saponins of total diets). Rice straw was used as a roughage source. The diet was fed ad libitum as a total mixed ration. SM pellets contained crude tannins and saponins at 12.1 and 15.7% of DM, respectively. It was found that at R:C 30:70 the DM intake and the digestibility of DM, CP and NDF were increased (p < 0.05), while SM pellet supplementation reduced the DM digestibility (p < 0.05). Ruminal pH was decreased at R:C 30:70. Total VFA and propionate was increased at high concentrate level and after SM pellet supplementation (p < 0.05); simultaneously, the acetate concentration and the acetate-to-propionate ratios were decreased (p < 0.05). Methane production was decreased at R:C 30:70 and additionally when SM pellets were supplemented (p < 0.05). This was in agreement with the percentage of methanogens in total ruminal DNA. Furthermore, the number of fungal zoospores were reduced at a higher concentrate proportion (R:C 30:70) and by SM-pellet supplementation (p < 0.05). Protozoal populations were diminished when SM pellets were supplemented (p < 0.05). In this study, it was shown that the roughage-to-concentrate ratio, as well as the supplementation of SM pellets containing condensed tannins and saponins, caused changes in ruminal microorganisms and their fermentation end-products.

Effect of dietary Quebracho tannin extract on feed intake, digestibility, excretion of urinary purine derivatives and milk production in dairy cows

The aim of this study was to evaluate the effects of dietary Quebracho tannin extract (QTE) on feed intake, apparent total tract digestibility (ATTD), excretion of urinary purine derivatives (PD) and milk composition and yield in dairy cows. Fifty Holstein cows were divided into two groups. To reach a similar performance of both groups, cows were divided according to their milk yield, body weight, days in milk and number of lactations at the start of the experiment averaging 33.2 ± 8.2 kg/d, 637 ± 58 kg, 114 ± 73 d and 2.3 ± 1.6 lactations, respectively. The cows were fed a basal diet as total mixed ration containing on dry matter (DM) basis 34% grass silage, 32% maize silage and 34% concentrate feeds. Three dietary treatments were tested, the control (CON, basal diet without QTE), QTE₁₅ (basal diet with QTE at 15 g/kg DM) and QTE₃₀ (basal diet with QTE at 30 g/kg DM). Two treatments were arranged along six periods each 21 d (13 d adaptation phase and 8 d sampling phase). The ATTD of DM and organic matter were reduced only in Diet QTE₃₀, whereas both QTE treatments reduced ATTD of fibre and nitrogen (N), indicating that QTE impaired rumen fermentation. Nevertheless, feed intake was unaffected by QTE. In Diet CON, urinary N excretion accounted for 29.8% of N intake and decreased in treatments QTE₁₅ and QTE₃₀ to 27.5% and 17.9%, respectively. Daily faecal N excretion increased in treatments CON, QTE₁₅ and QTE₃₀ from 211 to 237 and 273 g/d, respectively, which amounted to 39.0%, 42.4% and 51.7% of the N intake, respectively. Hence, QTE shifted N excretion from urine to faeces, whereas the proportion of ingested N appearing in milk was not affected by QTE (average 30.7% of N intake). Daily PD excretion as indicator for microbial crude protein (CP) flow at the duodenum decreased in treatment QTE₃₀ compared with Diet CON from 413 to 280 mmol/d. The ratios of total PD to creatinine suggest that urinary PD excretion was already lower when feeding Diet QTE₁₅. While there was no effect of Diet QTE₁₅, treatment QTE₃₀ reduced milk yield, milk fat and protein. Both QTE treatments reduced milk urea concentration, which suggest that ruminal degradation of dietary CP was reduced. In summary, adding QTE at dosages of 15 and 30 g/kg DM to diets of lactating dairy cows to improve feed and protein use efficiency is not recommended.

The effects of graded levels of dietary tannin on the epithelial tissue of the gastro-intestinal tract and liver and kidney masses of Boer goats

This study was conducted to determine the effects of different levels of dietary tannin on gastrointestinal tract (GIT) histology and on liver and kidney masses. Five groups of Boer goats were given diets containing 0, 50, 100, 150 and 200 g/kg of tannin for 6 weeks before data collection. Differences in the histopathology of the oesophagus, reticulum, rumen, omasum, abomasum and duodenum were evaluated. Increased dietary tannin levels induced thickening and/or keratinization of epithelial tissue in the reticulum, rumen, omasum and abomasum. Increased tannin levels also resulted in a loss of epithelial cells, erosion of microvilli and shortened villi height in the duodenum, which could impair the absorption of nutrients. Consequently, condensed tannins had a negative effect on the histopathology of the Boer goats.

Effects of Juniperus species and stage of maturity on nutritional, in vitro digestibility, and plant secondary compound characteristics

Rising feed costs and recurring feed shortages necessitate the investigation into alternative and underutilized feed resources. Nutritional characteristics of species are either unknown or limited to leaves and ground material from small stems. Therefore, the objective was to quantify nutritional characteristics, 48-h true IVDMD (tIVDMD), microbial gas production, and secondary compound characteristics of entire woody plant material of 4 species-, , , and -at immature and mature stages of growth. Immature plants had greater CP concentrations and lower NDF concentrations ( < 0.001) than mature plants regardless of species. Mature plants also had greater ( < 0.001) concentrations of ADF compared with immature plants with the exception of . In general, immature , , and had greater ( < 0.02) tIVDMD and total 48-h and asymptotic gas production than mature plants. Immature and plants were more digested (tIVDMD; < 0.001) than immature and , but tIVDMD did not differ in mature plant material across species. Condensed tannins (CT) were greater ( < 0.001) in immature and than mature plants; differences in CT concentrations among immature species were also detected ( < 0.04). Volatile oil yields were similar across maturity and species with 1 exception: immature yielded more ( < 0.02) volatile oil than mature material. Volatile oil composition across species varied and contained a range of 65 to 70 terpene compounds. The dominant terpenes across species were generally greater ( < 0.05) in immature vs. mature plant material with the exception of . Labdane acids were negligible in , , and and greater in ( < 0.001). Ground material from mature juniper species, although inferior in nutritional quality compared with immature plants, is comparable to traditional low-quality roughage ingredients. Given that has been successfully fed in lamb feedlot diets, the similarities of , and suggest that all three species have potential to be effective roughage ingredients.

Potential of tannin-rich plants, Leucaena leucocephala, Glyricidia sepium and Manihot esculenta, to reduce enteric methane emissions in sheep

An in vivo trial was conducted in sheep to investigate the effect of three tropical tannin-rich plants (TRP) on methane emission, intake and digestibility. The TRP used were leaves of Glyricidia sepium, Leucaena leucocephala and Manihot esculenta that contained, respectively, 39, 75 and 92 g condensed tannins/kg DM. Methane was determined with the sulphur hexafluoride tracer technique. Eight rumen-cannulated sheep of two breeds (four Texel, four Blackbelly) were used in two 4 × 4 Latin square designs. Four experimental diets were tested. They consisted in a tropical natural grassland hay based on Dichanthium spp. fed alone (C) or in association with G. sepium (G), L. leucocephala (L) or M. esculenta (M) given as pellets at 44% of the daily ration. Daily organic matter intake was higher in TRP diets (686, 984, 1054 and 1186 g/day for C, G, L and M respectively; p < 0.05) while apparent organic matter total tract digestibility was not affected (69.9%, 62.8%, 65.3% and 64.7% for C, G, L and M respectively; p > 0.05). Methane emission was 47.1, 44.9, 33.3 and 33.5 g/kg digestible organic matter intake for C, G, L and M, respectively, and was significantly lower (p < 0.05) for L and M than for G and C. Our results confirm the potential of some TRP to reduce methane production. The strong decrease in methane and the increase in intake with TRPs may be due to their presentation as pellets.

Effects of different concentrations of ground oak acorn on growth performance, blood parameters and carcass characteristics of goat kids

The objective of the present study was to evaluate the effect of different levels of ground oak acorn on growth performance, blood parameters and carcass characteristics. Twenty-four goat kids averaging 16.93 ± 1.25 kg initial bodyweight were randomly assigned to four experimental diets in a completely randomised design for 90 days. The experimental diets consisted of (1) 0% oak acorn (control), (2) 8% oak acorn, (3) 17% oak acorn and (4) 25% oak acorn on a DM basis. The goats were slaughtered after 105 days of feeding and carcass characteristics were measured. DM intake increased linearly in small amounts as the level of acorn in the diet increased (P < 0.004). The results showed that average daily gain, water intake and feed conversion ratio were unaffected by levels of ground oak acorn (P > 0.05). There were no significant differences in blood parameters (P > 0.05). Carcass fat depth and abdominal fat weight decreased with increasing ground oak acorn in the diet. Other carcass characteristics were not affected by different levels of ground oak acorn. On the basis of the results of the present study, it may be concluded that ground oak acorn can be used up to 25% in the diets of young goats without any adverse effects on growth performance and carcass characteristics. At this level of acorns, the goats received low concentrations of hydrolysable tannins (11 g/kg DM) in their diet.

Effects of Protein Level and Mangosteen Peel Pellets (Mago-pel) in Concentrate Diets on Rumen Fermentation and Milk Production in Lactating Dairy Crossbreds

Four, lactating dairy crossbreds (50%×50% Holstein Friesian×Native Zebu cattle) were randomly assigned according to a 2×2 factorial arrangement (two protein levels and two levels of mangosteen peel pellets (Mago-pel)) in a 4×4 Latin square design to receive four dietary treatments. All cows received concentrate at a proportion of 1 kg concentrate per 2 kg of milk yield, and urea-treated 5% rice straw (UTRS) was given ad libitum. It was found that total dry matter intakes, nutrient digestibility, ruminal pH and NH₃-N concentrations were not affected (p>0.05) by treatments. Concentrations of ruminal pH and NH₃-N were not affected by dietary treatments although the concentration of BUN varied significantly (p<0.05) between protein levels (p<0.05). The populations of rumen bacteria and fungal zoospores did not differ among treatments (p>0.05); however, the population of protozoa was decreased (p<0.05) when cows received Mago-pel supplementation. The composition of the population of bacteria, identified by real-time PCR technique, including total bacteria, methanogens, Fibrobacter succinogenes and Ruminococcus albus was similar (p>0.05) among dietary treatments (p>0.05); however, copy numbers of Ruminococcus flavefaciens was increased when protein level increased (p<0.05). Microbial protein synthesis, in terms of both quantity and efficiency, was enriched by Mago-pel supplementation. Milk yield was greatest in cows fed UTRS based diets with concentrate containing protein at 16% CP with Mago-pel, but were lowest without Mago-pel (p<0.05). In addition, protein level and supplementation of Mago-pel did not affect (p>0.05) milk composition except solids-not-fat which was higher in cows fed the diet with 19% CP. Therefore, feeding a concentrate containing 16% CP together with 300 g/hd/d Mago-pel supplementation results in changes in rumen fermentation and microbial population and improvements in milk production in lactating dairy crossbreds fed on UTRS.

In vitro protein degradation of 38 sainfoin accessions and its relationship to tannin content by different assays

This study compared 38 sainfoin and 2 Lotus accessions to their respective tannin contents, N buffer solubility, and in vitro protein degradation. Tannin contents were measured by a protein precipitation method using either bovine serum albumin or Rubisco and by the colorimetric HCl/butanol method. Precipitation of bovine serum albumin and Rubisco was highly correlated (R(2) = 0.939). Correlations between the protein precipitation variants and the HCl/butanol method were relatively low (R(2) < 0.6). Protein degradation was measured at 4 h of incubation in an inhibited in vitro system and could not be explained by any of the tannin assays (R(2) < 0.03) and only partially by N buffer solubility (R(2) ≤ 0.433). Decisive factors other than the quantity of tannins or their ability to precipitate proteins must be considered. Resistance of soluble protein toward degradation can possibly be caused by tannin protein binding.

Effect of field peas, chickpeas, and lentils on rumen fermentation, digestion, microbial protein synthesis, and feedlot performance in receiving diets for beef cattle

Two experiments were conducted to evaluate the use of pulse grains in receiving diets for cattle. In Exp. 1, 8 Holstein (615 +/- 97 kg of initial BW) and 8 Angus-crossbred steers (403 +/- 73 kg of initial BW) fitted with ruminal and duodenal cannulas were blocked by breed and used in a randomized complete block design to assess the effects of pulse grain inclusion in receiving diets on intake, ruminal fermentation, and site of digestion. Experiment 2 was a 39-d feedlot receiving trial in which 176 mixed-breed steers (254 +/- 19 kg of initial BW) were used in a randomized complete block design to determine the effects of pulse grains on DMI, ADG, and G:F in newly received feedlot cattle. In both studies, pulse grains (field peas, lentils, or chickpea) replaced corn and canola meal as the grain component in diets fed as a total mixed ration. Treatments included 1) corn and canola meal (control); 2) field pea; 3) lentil; and 4) chickpea. Preplanned orthogonal contrasts were conducted between control vs. chickpea, control vs. field pea, and control vs. lentil. In Exp. 1, there were no differences among treatments for DMI (11.63 kg/d, 2.32% of BW daily, P = 0.63) or OM intake (P = 0.63). No treatment effects for apparent ruminal (P = 0.10) and total tract OM digestibilities (P = 0.40) were detected when pulse grains replaced corn and canola meal. Crude protein intake (P = 0.78), microbial CP flow (P = 0.46), total tract CP digestibility (P = 0.45), and microbial efficiency (P = 0.18) were also not influenced by treatment. Total-tract ADF (P = 0.004) and NDF (P = 0.04) digestibilities were greater with field pea vs. control. Total VFA concentrations were lower for field pea (P = 0.009) and lentil (P < 0.001) compared with control. Chickpea, field pea, and lentil had lower (P < or = 0.03) acetate molar proportion than control. Ruminal pH (P = 0.18) and NH3 (P = 0.14) were not different among treatments. In Exp. 2, calves fed chickpea, field pea, and lentil had greater overall DMI (7.59 vs. 6.98 kg/d; P < or = 0.07) and final BW (332 vs. 323 kg; P < or = 0.04), whereas chickpea and lentil had greater ADG (1.90 vs. 1.71 kg/d; P < or = 0.04) than control. Gain efficiency (P = 0.18) did not differ among treatments. Steers fed pulse grains had similar CP and OM digestibilities compared with a combination of corn and canola meal in receiving diets. Pulse grains are a viable alternative for replacement of protein supplements in receiving diets for beef cattle.

Effects of Moringa oleifera seed extract on rumen fermentation in vitro

Moringa oleifera is a pantropical tree of the family Moringaceae. A previously undescribed property of an aqueous extract from the seeds of this plant is the modulation of ruminal fermentation patterns, especially protein degradation, as demonstrated in a short-term batch incubation system. Gas, short chain fatty acids (SCFA) and cellulolytic enzyme activities were determined as general fermentation parameters. A dot blot assay able to directly detect true protein in rumen fluid samples was used to quantify protein degradation. For complex substrates the interpretation of protein degradation profiles was amended by polyacrylamide gel electrophoresis (PAGE) of the samples. When incubated with pure carbohydrates at a concentration of 1 mg ml(-1), the extract reduced microbial degradation of the model protein, bovine serum albumin (BSA), such that its concentration was at least 40% above the control after 12 h of incubation. Total protein degradation was thus delayed by approximately 9 h. When fermented along with wheat straw, leaf protein (Rubisco) was almost entirely protected during 12 h of fermentation. The degradation of soy proteins was retarded by at least 4-6 h, depending on the protein band. There were strong side effects on the fermentation of pure cellulose (SCFA yield-60% after 12 h), whereas cellobiose and starch fermentation were less affected (-18 and -8%, respectively). When the complex substrates were fermented, SCFA yield was reduced by approximately 30% after 12 h. In our work we clearly demonstrate the efficacy of the new substance, which is neither a tannin nor a saponin, in an in vitro system, using pure as well as complex substrates. The properties shown in vitro for the crude extract suggest that it could have a positive effect on the protein metabolism of ruminants under intensive management and that negative side effects can be overcome by an optimized dosage. If the chemical nature of the active substance and its mechanism of action can be clarified, it may provide an alternative to replace critical synthetic feed additives (such as antibiotics) for high yielding dairy cows.