In vitro evidence for the importance of cultivation conditions on the effects of Calliandra tannins on ruminal escape of soybean protein and its post‐ruminal degradability

Purified condensed tannins (CT) extracted from the legume Calliandra calothyrsus (var. San Ramón CIAT 22310), harvested in the dry and the rainy season and cultivated with low or high level of fertilization were added to soybean meal in a ratio of 600 mg/g of the incubated crude protein (CP). Effects on degradation either in ruminal fluid only, or in ruminal fluid followed by incubation in HCl/pepsin, were evaluated using a modified two‐step in vitro method. Season was found to have larger effects on in vitro ruminal and post‐ruminal CP degradation than fertilization. Condensed tannins from the rainy season harvest reduced ruminal CP degradation less than that from the dry season harvest. They had also less negative effects on the degradability of rumen escape protein and enhanced the proportion of post‐ruminally degraded CP more than CT from the dry season harvest. An increase in level of fertilization reduced ruminal CP degradation in CT from the rainy season plants but this was not associated with effects on post‐ruminal degradation. The study demonstrated the importance of environmental factors for the efficiency of CT in modifying ruminal and post‐ruminal CP degradation.     

Impact of variation in structure of condensed tannins from sainfoin (Onobrychis viciifolia) on in vitro ruminal methane production and fermentation characteristics

Our study investigated the effects of condensed tannins (CT) on rumen in vitro methane (CH₄) production and fermentation characteristics by incubating lucerne in buffered rumen fluid in combination with different CT extracts at 0 (control), 40, 80 and 120 g CT/kg of substrate DM. Condensed tannins were extracted from four sainfoin accessions: Rees ‘A’, CPI63763, Cotswold Common and CPI63767. Gas production (GP) was measured using a fully automated GP apparatus with CH₄ measured at distinct time points. Condensed tannins differed substantially in terms of polymer size and varied from 13 (Rees ‘A’) to 73 (CPI63767) mean degree of polymerization, but had relatively similar characteristics in terms of CT content, procyanidin: prodelphinidin (PC: PD) and cis:trans ratios. Compared to control, addition of CT from CPI63767 and CPI63763 at 80 and 120 g CT/kg of substrate DM reduced CH₄ by 43% and 65%, and by 23% and 57%, respectively, after 24‐h incubation. Similarly, CT from Rees ‘A’ and Cotswold Common reduced CH₄ by 26% and 46%, and by 28% and 46% respectively. Addition of increasing level of CT linearly reduced the maximum rates of GP and CH₄ production, and the estimated in vitro organic matter digestibility. There was a negative linear and quadratic (p < 0.01) relation between CT concentration and total volatile fatty acid (VFA) production. Inclusion of 80 and 120 g CT/kg of substrate DM reduced (p < 0.001) branched‐chain VFA production and acetate: propionate ratio and was lowest for CPI63767. A decrease in proteolytic activity as indirectly shown by a change in VFA composition favouring a shift towards propionate and reduction in branched‐chain VFA production varied with type of CT and was highest for CPI63767. In conclusion, these results suggest that tannin polymer size is an important factor affecting in vitro CH₄ production which may be linked to the CT interaction with dietary substrate or microbial cells.     

Chemical composition,nitrogen degradability and in vitro ruminal biological activity of tannins in vines harvested from four tropical sweet potato (Ipomoea batatas L.) varieties

This study investigated the potential of vines from four sweet potato varieties (Tia Nong 57, Tia Nong 66, Ligwalagwala and Kenya) as alternative feed resources for ruminant livestock. The chemical composition [neutral detergent fibre (NDF), acid detergent fibre (ADF), crude protein (CP) and acid detergent insoluble nitrogen (ADIN)], in vitro ruminal nitrogen (N) degradability and in vitro ruminal biological activity of tannins in the vines, harvested at 70 and 110 days after planting (DAP), were determined. Variety and harvesting stage did not (p > 0.05) influence CP and NDF content of the vines. Concentration of CP ranged from 104.9 to 212.2 g/kg DM, while NDF ranged from 439.4 to 529.2 g/kg DM across harvesting stages and varieties. Nitrogen degradability (ND) at 70 and 110 DAP was highest (p < 0.05) in Ligwalagwala (743.1 and 985.0 g/kg DM, respectively). Treatment of vines with tannin‐binding polyethylene glycol (PEG) increased (p < 0.05) in vitro ruminal cumulative gas production parameters (a, b and c). The in vitro ruminal biological activity of tannins, as measured by increment in gas production parameters upon PEG inclusion, had a maximum value of 18.2%, suggesting low to moderate antinutritional tannin activity. Ligwalagwala vines, with highly degradable N, would be the best protein supplement to use during the dry season when ruminant animals consume low N basal diets and maintenance is an acceptable production objective. Tia Nong 66 and Kenya varieties, with less degradable N, may be more suitable for use as supplements for high‐producing animals such as dairy goats.     

Prevalence and consequence of subacute ruminal acidosis in Polish dairy herds

The aim of this study was to estimate the prevalence of subacute ruminal acidosis (SARA) in Polish high‐yielding dairy herds. Also, the relationships between the chemical composition of the diet and the feed particle size, ruminal pH and the occurrence of this metabolic disease and the fermentation profile were determined. Rumen fluid samples were obtained from a total of 213 cows from nine dairy herds (≥20 cows per herd) via rumenocentesis. Almost 14% (30/213) of cows as acidotic (pH<5.6) were found, which is indicative of SARA. Moreover, 44% of the herds were classified as SARA‐positive and 56% as SARA‐negative. Results of the current study suggested that the physically effective NDF (NDF_>1.18 mm)‐to‐starch ratio could be better indices than peNDF_>1.18 mm to preventing the occurrence of SARA, and their level should not be lower than 1.00. Also, linear negative relationships between rumen fluid pH and concentration of propionate, valerate and total VFA were determined. According to the herd's SARA status and rumen fluid biochemical indices, there were significant differences between the pH of rumen fluid (p ≤ 0.01), concentrations of acetate (p ≤ 0.05), propionate (p ≤ 0.05), n‐butyrate (p ≤ 0.01), n‐valerate (p ≤ 0.01), the sum of VFA (p ≤ 0.01) and ammonia (p ≤ 0.05) in SARA‐positive herds compared to SARA‐negative herds. The better understanding the strategy of ruminant nutrition to coordinate energy conversion and the role of the ruminal pH in regulating N‐NH₃ production, absorption through rumen mucosa, urea secretion, the more successfully we can utilize these processes with due recognition of animal needs and welfare, as well as prevention of SARA occurrence.     

Responses to condensed tannins of flowering sulla (Hedysarum coronarium L.) grazed by dairy sheep: Part 2: Effects on milk fatty acid profile

A grazing experiment was undertaken to evaluate the effect of PEG supplementation on the fatty acid composition of milk from Sarda sheep grazing sulla. Twenty-four late-lactating sheep (12 per group), were paired and split into two groups: group control (CON), dosed daily with a quenching gun with 200 ml of water, and group PEG, dosed with 200 ml of a 50/50 w/v water solution of PEG. The sheep grazed two 0.8 ha plots of sulla under a rotational grazing scheme.The contents of c-9, t-11 CLA and t-11 C18:1 in milk fat were on average 40% higher (P < 0.01) in the PEG group than in the CON group. This can be explained by the higher biohydrogenation activity of ruminal bacteria in the PEG group, due to the partial inactivation of the tannins. Odd-branched chain fatty acids (OBCFA) were higher in PEG than in the control group (+ 20%; P < 0.01) and this confirms the hypothesis that tannin in sulla reduced ruminal microbial activity. Both linoleic (C18:2 c-9 c-12) and linolenic (C18:3 c-9 c-12 c-15) fatty acids were lower (P < 0.05) in milk from PEG, than in the CON-group (− 12% and − 30% for linoleic and linolenic acids, respectively). The mitigating effect on tannins of PEG increased the ratio of ω6/ω3 by 24%; (P < 0.01) and total trans FA content in milk by 20% (P < 0.01). In conclusion, condensed tannins in sulla at flowering are conducive to lower c-9, t-11 CLA and t-11 C18:1 but also lower total trans FA, ω6/ω3 ratio and higher linoleic and linolenic acid.     

The effect of supplementing leaves of four tannin‐rich plant species with polyethylene glycol on digestibility and zootechnical performance of zebu bulls (Bos indicus)

The effect of supplementing leaves of four tannin‐rich plant species with polyethylene glycol 6000 (PEG) on nutrient intake and digestibility as well as on weight gain, feed conversion ratio (FCR) and N retention of zebu bulls (Bos indicus) was studied. Leaves of Albizia gummifera, Grewia ferruginea, Prunus africana and Syzygium guineense, containing, respectively, 85, 55, 76 and 172 g condensed tannins (CT) per kg dry matter (DM), were combined with natural pasture hay in a ratio of 40:60 on DM basis. The four diets were fed both without and with addition of PEG, at a dose of 40 g per kg DM, to eight zebu bulls during trials of 25 days in an 8 × 8 randomized crossover design. Supplementation with PEG increased nutrient intake, digestibility, FCR, N retention and average daily gain (p < 0.01). A diet × PEG interaction was observed for nutrient intake as well as for crude protein, neutral detergent fibre and acid detergent fibre digestibility (p < 0.05), but the effect size of PEG addition could not be attributed to the CT content as such, and also digestibility without PEG was not related to CT content of the diets. The reason why the efficacy of PEG addition did not relate to the CT content pointed the need to evaluate other factors that can help to predict the efficacy of PEG, for example, tannin type or interaction with other nutrients.     

Buffer nitrogen solubility,in vitro ruminal partitioning of nitrogen and in vitro ruminal biological activity of tannins in leaves of four fodder tree species

This study explores the chemical composition, buffer N solubility, in vitro ruminal N degradability and in vitro ruminal biological activity of tannins in leaves from Gliricidia sepium, Leucaena leucocephala, Morus alba and Trichanthera gigantea trees. These tree leaves are a potential protein source for ruminants, but their site‐influenced nutritive value is largely unknown. Leucaena leucocephala leaves had the highest N content (42.1 g/kg DM), while T. gigantea leaves had the least (26.1 g/kg DM). Leucaena leucocephala had the highest buffer solubility index (20%), while 10% of the total N in leaves of the other three species was soluble. The rapidly fermentable N fraction ‘a’ was highest in M. alba leaves (734.9 g/kg DM) and least in T. gigantea leaves (139.5 g/kg DM). The rate of fermentation (c) was highest for M. alba (7%/hours) leaves. No significant correlations were recorded between buffer solubility index of N and in vitro ruminal N degradability parameters: a, b, and c. The highest response to tannin inactivation using polyethylene glycol, in terms of percentage increase in 36‐hours cumulative gas production, was recorded in M. alba (39%) and T. gigantea (38%) leaves. It was concluded that buffer solubility of N is not a good indicator of ruminal N degradation in the leaves of these tree species. Leaves of M. alba could be more valuable as a source of rapidly fermentable N when animals are offered low‐protein, high‐fibre diets compared with other tree species evaluated in the current study. However, when feeding M. alba leaves, the role of tannins must be considered because these secondary plant compounds showed significant in vitro ruminal biological activity.     

Influence of harvesting site on chemical composition and potential protein value of Acacia erioloba,A. nilotica and Ziziphus mucronata leaves for ruminants

This study was designed to evaluate the chemical composition, buffer N solubility, in vitro ruminal N degradation and in vitro ruminal biological activity of condensed tannins in Acacia erioloba, Acacia nilotica and Ziziphus mucronata leaves harvested from two sites (Masuthle communal grazing land and Molelwane private farm). Leaves were harvested, dried at 60 °C and milled. The highest crude protein (CP) content was found in leaves of Z. mucronata (177.7 g/kg DM). Leaves harvested from Masuthle had higher (p < 0.05) soluble phenolics (SPh) (44.6 g TAE/kg DM) compared to those harvested from Molelwane (29.8 g TAE/kg DM). In both Molelwane and Masuthle, leaves of A. nilotica had higher levels of condensed tannins (CT) (0.76 AU_550/200 mg and 0.52 AU_550/200 mg respectively) followed by A. erioloba and Z. mucronata, which did not differ (p > 0.05). Nitrogen degradability at 24 h was the same (p > 0.05) for all tree species but not at 12 and 36 h. No linear association (p > 0.05) was found between buffer‐soluble N and in vitro ruminal N degradability in leaves with high SPh content. The largest polyethylene glycol (PEG) effect was in leaves of A. nilotica (448%) harvested from Masuthle after 36 h of incubation. Ziziphus mucronata leaves harvested from Molelwane had the least PEG effect at 48 h. There was no linear association (p > 0.05) between PEG effect and SPh for all incubation periods, but a positive relationship was observed between PEG effect and condensed tannins content. There was no linear association between solubility index (SI) and in vitro ruminal N degradability for tannin‐rich leaves. It was concluded that higher browsing pressure in Masuthle communal rangeland resulted in leaves with higher levels of condensed tannins, which had higher in vitro ruminal biological activity, compared to those harvested from Molelwane.     

Nutritional evaluation of the legume Macrotyloma axillare using in vitro and in vivo bioassays in sheep

This study consisted of two experiments with the following objectives: to evaluate the effects of tannins from the tropical legume macrotiloma (Macrotyloma axillare) on total gas and methane (CH₄) production, as well as on ruminal fermentation parameters by performing an in vitro bioassay, with samples incubated with and without polyethylene glycol (PEG) in a semi‐automatic system; and secondly in a 17 day in vivo experiment, to determine apparent total tract digestibility (ATTD) of dietary nutrients and ruminal fermentation parameters of 12 intact 8‐ to 9‐month‐old Santa Inês (averaging 24.95 ± 1.8 kg body weight) ewes fed tropical grass hay supplemented with macrotiloma hay. The ewes were divided into two treatment groups depending on their diet: chopped aruana grass hay (Panicum maximum cv. Aruana) (control—CON); and aruana grass hay supplemented with chopped macrotiloma hay (macrotiloma—MAC). The animals were kept for 5 consecutive days in metabolic cages for the ATTD assay, and at the end of this period, samples of rumen fluid were collected from each ewe to determine ammoniacal nitrogen (NH₃‐N) and short‐chain fatty acid (SCFA) production, and protozoa count. For the in vitro assay, a decrease in total gas and CH₄ production was observed for samples incubated without PEG (p < .05). No differences were observed for the other parameters evaluated (p > .05). In the in vivo experiment, increased intake and ATTD of crude protein were observed for the animals fed MAC when compared to CON (p < .05). For rumen fermentation parameters, increased NH₃‐N, total SCFA and isobutyrate concentrations, as well as reduced protozoa count were observed for MAC when compared to CON (p < .05). The results observed here indicated the potential of macrotiloma for use as a ruminant feed, and antimethanogenic potential of this plant was noted.     

Effect of feeding Acacia nilotica pods to sheep on nutrient digestibility,nitrogen balance,ruminal protozoa and rumen enzymes activity

This study was conducted to evaluate the effect of supplying two levels of Acacia nilotica (A. nilotica) pods to rations of sheep on nutrient digestibility, nitrogen balance and rumen liquor parameters (pH, total protozoa count, protein concentration and enzymes activity). Twelve mature rams (50 ± 1.25 kg B.W.) were distributed into three groups, each with four rams. Animals in group one were considered as a control which fed a basal diet, consisting of concentrate mixture and Egyptian clover. The second group and the third one received the same basal diet with supplying the concentrate mixture by 1.5% and 3.0% of A. nilotica pods meal respectively. The experiment lasted for 3 weeks. It was found that supplementation of A. nilotica pods to the concentrate mixture at a rate of 1.5% and 3.0% significantly improved the total feed intake compared to the control. The digestibility of dry matter and crude fibre was significantly reduced with A. nilotica supplements, whereas the digestibility of crude protein was significantly improved. All of nitrogen intake and N‐retained were significantly increased in rams fed on concentrates with 1.5% and 3.0% A.  nilotica pods when compared to the control. The pH of ruminal fluid was not affected by the dietary treatments. Nevertheless, the total rumen protozoa count was significantly decreased in A. nilotica pods supplemented groups. Also, the rumen protein concentration and the ruminal enzymes activity, especially α‐amylase, cellulase and protease, were lower in A. nilotica pods supplemented treatments. In conclusions, inclusion of low levels of A. nilotica pods (1.5% and 3.0%) in the concentrates can be used as a natural protein protectant in ruminants by forming tannin protein complexes in the rumen to maximize the amino acids available in the lower digestive tract. Also, these levels can increase the protein digestibility as well as the N‐retained in the body .     

Effect of feeding tannin degrading bacterial culture (Streptococcus gallolyticus strain TDGB 406) on nutrient utilization,urinary purine derivatives and growth performance of goats fed on Quercus semicarpifolia leaves

To study the effect of supplementation of tannin degrading bacterial culture (Streptococcus gallolyticus strain TDGB 406) on growth performance, nutrient utilization and urinary purine derivatives of goats fed on oak (Quercus semicarpifolia) leaves. For growth study, eighteen billy goats (4 month old, average body weight 9.50 ± 1.50 kg) were distributed into three groups of six animals each. The animals of group 1 served as control while animals of groups 2 (T1) and 3 (T2) were given (@ 5 ml/kg live weight) autoclaved and live culture of isolate TDGB 406 (10⁶ cells/ml) respectively. The animals were fed measured quantity of dry oak leaves as the main roughage source and ad libitum maize hay along with fixed quantity of concentrate mixture. The feeding of live culture of isolate TDGB 406 (probiotic) did not affect dry matter intake and digestibility of nutrients except that of dry matter and crude protein, which was higher in T2 group as compared to control. All the animals were in positive nitrogen balance. There was no significant effect of feeding isolate TDGB 406 on urinary purine derivatives (microbial protein production) in goats. The body weight gain and average live weight gain was significantly higher (p = 0.071) in T2 group as compared to control. Feed conversion efficiency was also better in the goats fed on live culture of TDGB 406 (T2). The feeding of tannin degrading bacterial isolate TDGB 406 as probiotic resulted in improved growth performance and feed conversion ratio in goats fed on oak leaves as one of the main roughage source.     

Effect of oral administration of probiotics on growth performance,apparent nutrient digestibility and stress‐related indicators in Holstein calves

This study aimed to investigate the effect of dietary supplementation with Lactobacillus plantarum and Bacillus subtilis on growth performance, apparent nutrient digestibility and stress‐related indicators in dairy calves. Twenty‐four neonatal Holstein calves were randomly allocated to three treatments: a basal diet with no supplementation (control), the basal diet supplemented with 1.7 × 10¹⁰ CFU per head per day (CFU/h.d) of L. plantarum GF103 (LB group) or the basal diet supplemented with a mixture of L. plantarum GF103 (1.7 × 10¹⁰ CFU/h.d) and B. subtilis B27 (1.7 × 10⁸ CFU/h.d) (LBS group). Dry matter intake (DMI), average daily gain (ADG), feed conversation ratio (FCR), apparent digestibility of nutrients and stress‐related indicators were measured in this trail. The result indicated that no significant differences were observed in DMI or ADG (p > 0.05), but the FCR was improved in the LB group over the first 12 weeks (p > 0.05). The apparent digestibility of nutrients was not altered by probiotics in week 6 (p > 0.05), but the apparent digestibility of total phosphorus was significantly greater in the LB and LBS groups in week 8 (p > 0.05); additionally, an increase in the apparent digestibility of crude protein was detected in the LBS group (p > 0.05). Oral administration of L. plantarum alone improved the T‐lymphocyte transformation rate on days 58 and 62 (p > 0.05), while adding the mixture of L. plantarum and B. subtilis increased the T‐lymphocyte transformation rate (p > 0.05) but decreased the content of cortisol on day 58 (p > 0.05). No significant differences were detected between the LB and LBS groups in growth performance, apparent digestibility of nutrients and stress‐related indicators (p > 0.05). The results suggested that oral administration of L. plantarum improved growth performance, nutrient digestibility and relieved weaning stress in calves, but no additional effect was obtained by supplementation with B. subtilis.     

Influence of protein fermentation and carbohydrate source on in vitro methane production

Incubations were carried out with batch cultures of ruminal micro‐organisms from sheep to analyse the influence of the N source on in vitro CH₄ production. The two substrates were mixtures of maize starch and cellulose in proportions of 75:25 and 25:75 (STAR and CEL substrates, respectively), and the three nitrogen (N) sources were ammonia (NH₄Cl), casein (CA) and isolated soya bean protein (SP). Five isonitrogenous treatments were made by replacing non‐protein‐N (NPN) with CA or SP at levels of 0 (NPN), 50 (CA50 and SP50, respectively) and 100% (CA100 and SP100) of total N. All N treatments were applied at a rate of 35 mg of N/g of substrate organic matter and incubations lasted 16.5 h. With both proteins, N source × substrate interactions (p = 0.065 to 0.002) were detected for CH₄ production and CH₄/total VFA ratio. The increases in CH₄ production observed by replacing the NPN with protein‐N were higher (p < 0.05) for STAR than for CEL substrate, but the opposite was observed for the increases in volatile fatty acid (VFA) production. As a consequence, replacing the NPN by increased levels of CA or SP led to linear increases (p < 0.05) in CH₄/total VFA ratio with STAR, whereas CH₄/total VFA ratio tended (p < 0.10) to be decreased with CEL substrate. Increasing the amount of both proteins decreased linearly (p < 0.05) ammonia‐N concentrations, which may indicate an incorporation of amino acids and peptides into microbial protein without being first deaminated into ammonia‐N. In incubations with the tested N sources as the only substrate, the fermentation of 1 mg of CA or SP produced 1.24 and 0.60 μmol of CH₄ respectively. The results indicate the generation of CH₄ from protein fermentation, and that the response of CH₄ production to protein‐N supply may differ with the basal substrate.     

Silage quality as influenced by concentration and type of tannins present in the material ensiled: A meta‐analysis

Protein degradation during ensiling is a major problem. Tannins are known to prevent or decelerate protein degradation in the rumen and may be able to do so in silages as well. Therefore, the present evaluation aimed to analyse the influence of tannins on silage quality. This was done by integrating from all suitable experiments found in literature on the topic in a meta‐analysis approach. A total of 122 datasets originating from 28 experiments obtained from 16 published articles and one own unpublished experiment were included in the database. Tannins in the silages originated either from the plants ensiled or from supplementations of tanniferous plants or tannins extracted from such plants. Tannin concentrations ranged from 0 to 57.8 g/kg dry matter, and the ensiling period varied from 30 to 130 days. The analysis was based on the linear mixed model methodology in which the different studies were considered as random effects and tannin‐related properties (either concentration or type of tannins) were treated as fixed effects. Results revealed that greater concentrations of tannins were associated with a decrease of butyrate concentration in the silages (p < 0.05). An increasing tannin concentration was also accompanied with smaller proportions of soluble N, free amino acid N, non‐protein nitrogen and NH₃‐N in total silage N (p < 0.05). The relationships between hydrolysable and condensed tannins and the decline in butyrate and NH₃‐N concentrations in the silages were of different magnitude (p < 0.05). A higher tannin concentration was associated with a decline in in vitro dry matter digestibility. It was concluded that tannins apparently have the ability to limit extensive proteolysis which may occur during ensiling and thus may improve the fermentative quality of silages. A desired side effect seems to be given by the tannins' apparent property to limit the activity of the butyrate‐producing microbes.     

Digestibility,ruminal fermentation,blood metabolites and antioxidant status in ewes supplemented with DL‐methionine or hydroxy‐4 (methylthio) butanoic acid isopropyl ester

The effects of supplementing ewe diets with either DL‐methionine (DL‐Met) or 2‐hydroxy‐4 (methylthio) butanoic acid isopropyl ester (HMBi) were investigated on ruminal in situ degradability of grain and forage diets, in vivo digestibility, rumen fermentation, blood metabolites and antioxidant status. Six ruminally cannulated ewes were used in a replicated 3 × 3 Latin square design with 28‐day periods. The dietary treatments were as follows: (i) no supplemental Met (control; CON), (ii) DL‐Met at 1.2 g/kg DM intake and (iii) HMBi at 1.8 g/kg dry matter (DM) intake. Corn grain, barley grain and alfalfa hay were evaluated for their ruminal degradability by both in situ incubation and effective degradability measurements of DM, neutral detergent fibre (NDF) and acid detergent fibre (ADF). Compared to other treatments, HMBi supplementation increased (p < 0.05) the digestibility of organic matter, crude protein and NDF and also tended (p = 0.08) to increase the digestibility of DM and ADF. Moreover, HMBi supplementation increased (p < 0.01) total VFA concentrations, the molar proportions of valerate and iso‐butyrate in the rumen. Compared to the CON treatment, DL‐Met and HMBi treatments tended (p = 0.08) to increase the molar proportion of acetate but decreased (p < 0.05) ruminal ammonia‐N concentration. Ewes supplemented with HMBi and DL‐Met recorded greater (p < 0.05) serum concentrations of glutathione peroxidase, total antioxidant capacity and superoxide dismutase than the CON treatment. Serum concentrations of glucose, total protein, albumin, high‐density lipoprotein and very low‐density lipoprotein were greater (p < 0.01) and serum urea nitrogen (p < 0.05), malonyl dialdehyde and triglyceride were lower (p < 0.02) in the HMBi and DL‐Met animals than in the CON ewes. The results concluded that HMBi is a very effective form of dietary Met supplementation for ewes with a positive effect on digestion, rumen fermentation and serum antioxidant function.     

The effect of maternal obesity on fatty acid transporter expression and lipid metabolism in the full‐term placenta of lean breed swine

This study was conducted to evaluate the influence of back‐fat thickness (BF), at mating of sows, on the maternal and newborn circulating lipids, expression of placental fatty acids (FA) transporters and lipid accumulation in placenta. Full‐term placentas were obtained by vaginal delivery from BFI (9–14 mm; n = 37), BFII (15–19 mm; n = 43) and BFIII (20–27 mm; n = 38) sows according to BF at mating, and frozen placental sections were analysed for fat accumulation. Blood samples were collected from the sows of day 105 pregnancy and from cord blood at delivery. mRNA and protein expression levels were evaluated with real‐time RT‐PCR and Western blotting. Our results demonstrated that BFII females had significantly increased litter weight and placental efficiency, decreased maternal triglyceride (TG) and non‐esterified fatty acids (NEFA) levels, decreased maternal IL‐6, TNFα and leptin levels compared to BFIII females (p < .05). BFIII sows were associated with significantly decreased newborn TG levels, increased newborn glucose, IL‐6 and TNFα levels compared to BFI or BFII sows (p < .05). BFI and BFII females had significantly decreased placental TG, NEFA and cholesterol (CHOL) contents compared to BFIII females (p < .05). Moreover, decreased CD36, FATP1, FABP4, and FABP1 mRNA and protein and FATP4 protein expression, and increased LPL activity were also observed in BFIII group compared with BFII group (p < .05). PPARγ mRNA and protein and lipogenic genes such as SREBP‐1c, ACSL1, ACCα, FAS and SCD mRNA expression were downregulated or upregulated, respectively, in the placentas of BFIII sows compared to BFI or BFII sows (p < .05). Overall, this study demonstrated that there is no advantage, in terms of litter live size, litter weight and placental FA transport and metabolism, in performing the mating of sows with BF>19 mm.     

Influence of condensed tannin on intake, digestibility, and efficiency of protein utilization in beef steers fed high concentrate diet

This trial was conducted to evaluate if the effect of condensed tannin (CT) is associated with a true protein source on intake, ruminal and total digestibility, ruminal digestion rate, protein efficiency, and microbial efficiency in beef steers fed high concentrate diet (87% of DM). Four Bos indicus steers (407 ± 12 kg of BW) fitted with rumen cannula were assigned to a 4 × 4 Latin square design, arranged in a 2 × 2 factorial arrangement. Treatments consisted of either inclusion (0.4% of DM) or exclusion of condensed tannin (CT) from quebracho extract (76% of CT) with or without the use of soybean meal (SBM) as source of true protein. The level of inclusion was calculated to provide a daily intake of 1 g/10 kg of BW of CT. Intake of DM and nutrients was not affected (P > 0.10) by CT inclusion. However, there was an effect (P < 0.10) of CT inclusion on ether extract digestibility. An interaction (P < 0.10) was observed between CT and SBM on ruminal digestibility and digestion rate of crude protein (CP): when mixed with soybean meal, CT decreased the ruminal digestibility and, consequently, reduced the digestion rate of CP. Intake of CP increased (P < 0.10) with the inclusion of SBM. No differences in DM passage rate were observed (P > 0.10) among treatments. Effects of the interaction (P < 0.10) between CT and SBM were observed on flux of rumen undegradable protein (RUP), metabolizable protein (MP), and on the ratio MP:CP. In the presence of soybean meal, the addition of CT increased (P < 0.10) the flux of RUP and MP, and improved the ratio MP:CP. The yield of microbial protein on the abomasum and the microbial efficiency did not differ among treatments (P > 0.10). There was no difference (P > 0.10) on the pH, VFA, and ruminal ammonia (N-NH₃) with the addition of condensed tannin. The N-NH₃ increased and the ruminal pH decreased with the inclusion of soybean meal (P < 0.10). The utilization of condensed tannin as an additive in beef cattle diets with high level of concentrate and soybean meal as a source of true protein implies positive effects on crude protein utilization, decreasing digestion rate and ruminal digestibility of crude protein and consequently increasing the levels of metabolizable protein, with no changes in the ruminal fermentation parameters.     

The relationships between odd‐ and branched‐chain fatty acids to ruminal fermentation parameters and bacterial populations with different dietary ratios of forage and concentrate

The objectives of this study were to investigate the effect of different dietary ratios of forage and concentrate (F:C) on ruminal odd‐ and branched‐chain fatty acids (OBCFAs) contents and to evaluate the relationships between OBCFA and ruminal fermentation parameters as well as bacterial populations tested by real‐time PCR technique. The experimental design was a 3 × 3 Latin square. Three rumen‐fistulated dry Holstein cows were fed three rations with different dietary F:C ratios (F:C; 30:70, 50:50 and 70:30). The rumen samples were collected every two hours (0600, 0800, 1000, 1200, 1400, 1600, 1800, 2000, 2200, 2400, 0200 and 0400 h) over three consecutive days in each sampling period. The results showed that rumen OBCFA profiles are significantly (p < 0.05) affected by the dietary F:C ratios. The concentrations of C11:0, C13:0, iso‐C15:0, iso‐C16:0, iso‐C17:0 and C17:0 were higher in the cows fed dietary F:C ratio of 70:30 than those fed with other two rations. However, the concentrations of anteiso‐C15:0, C15:0 and total OBCFA were on the lowest level in the high forage diet. Correlation and regression analysis showed that ruminal OBCFAs had strong relationships with ruminal fermentation parameters and bacterial populations. In particular, the iso‐fatty acids had potential power to predict butyrate and isoacids metabolized in the rumen, whereas the fatty acids with 17 carbon atoms correlated with ruminal NH₃‐N content. The OBCFA contents have different relationships with fibrolytic and starch bacteria in the rumen. C17:0 and its isomers might be used to predict populations of fibrolytic bacteria.     

Effects of Lonicera japonica extract supplementation on in vitro ruminal fermentation,methane emission,and microbial population

Lonicera japonica (LJ; honeysuckle) is used in traditional folk medicine in Korea and is a rich source of ascorbic acid and phenolic components that are reported to have antioxidant and antibiotic properties. We performed an in vitro experiment to assess the effects of LJ extracts (LJE) on ruminal fermentation. Timothy hay (0.3 g dry matter [DM]) was incubated with buffer, ruminal fluid, and 0%, 3%, 5%, 7%, and 9% LJE. Batch culture fermentation was conducted separately for 12, 24, and 48 hr to determine gas production (GP), ruminal fermentation characteristics, and microbial population characteristics. The effects on GP were generally similar to those on DM degradability, with a linear decrease observed at 9% extract at 24 hr. NH₃‐N showed a linear increase with increasing extract concentrations at 12 hr, whereas a decrease was observed at 24 hr. Extract supplementation decreased methane (CH₄) production at 12, 24, and 48 hr. In addition, the abundance of fibrolytic bacteria and ciliate‐associated methanogen was reduced at all concentrations of extracts. These results indicate that LJE have the potential to serve as a ruminal fermentation modifier to suppress CH₄ production with minimal effects on nutrient digestion in the rumen.     

Efficacy of Megasphaera elsdenii inoculation in subacute ruminal acidosis in cattle

Two consecutive experiments were carried out to determine efficacy of Megasphaera elsdenii inoculation in alleviation of subacute ruminal acidosis (SARA). In the first experiment, SARA was induced by feeding corn‐ and wheat‐based diets (20%, 40%, 60% and 80% of TMR, DM basis) in six ruminally cannulated heifers. Continuous pH was obtained using data loggers embedded in rumen. In corn (80%)‐ and wheat (60%)‐based diets ruminal pH ranged from 5.2 to 5.6 for 7.77 and 5.93 hr. In the second experiment (5 day), M. elsdenii (200 ml; 2.4 x 10¹⁰ cfu/ml) was inoculated during the first two days. During the SARA induction period, M. elsdenii and S. bovis in rumen liquor were more abundant in wheat‐based feeding (7.97 and 8.77) than in corn‐based feeding (7.06 and 7.95 per ml, log basis; p < 0.0001 for both). M. elsdenii inoculation increased total volatile fatty acids (VFA) concentration when corn‐based diet was fed, whereas it decreased total VFA concentration when wheat‐based diet was fed (p < 0.004). There was a decrease in the propionic acid proportion (24.04%–19.08%; p < 0.002), whereas no alteration in lactate and ammonia concentrations was observed. M. elsdenii inoculation increased protozoa count (from 5.39 to 5.55 per ml, log basis; p < 0.009) and decreased S. bovis count (from 9.18 to 7.95 per ml, log basis; p < 0.0001). The results suggest that M. elsdenii inoculation may help prevent SARA depending on dietary grain through altering rumen flora as reflected by a decrease in S. bovis count and an increase in protozoa count.