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.     

Effects of tributyrin supplementation on ruminal microbial protein yield,fermentation characteristics and nutrients degradability in adult Small Tail ewes

Two trials were conducted to assess the effects of tributyrin (TB) supplementation on ruminal microbial protein yield and fermentation characteristics in adult sheep. In an in vitro trial, substrate was made to offer TB at 0, 2, 4, 6, and 8 g/kg on a dry matter (DM) basis and incubated for 48 hr. In an in vivo trial, 45 adult ewes were randomly assigned by initial body weight (55 ± 5 kg) to five treatments of nine animals over an 18‐day period. Total mixed ration was made to offer TB to ewes at 0, 2, 4, 6, and 8 g/kg on a DM basis. The in vitro trial showed that TB enhanced apparent degradation of DM (p = .009), crude protein (p < .001), neutral detergent fiber (p = .007) and acid detergent fiber (p = .010) and increased methanogenesis (p < .001), respectively. The in vivo trial showed that TB decreased DM intake (p < .001) and enhanced rumen microbial N synthesis (p < .001), respectively. Both in vitro and in vivo trials showed that TB increased total volatile fatty acid concentration and enhanced fibrolytic enzyme activity. The results indicated that TB might exert positive effects on microbial protein yield and fermentation in the rumen.     

Use of NaHCO3 and MgO as additives for sheep fed only pasture for a restricted period of time per day: effects on intake,digestion and the rumen environment

Effects of NaHCO₃ and MgO buffer addition on intake and digestive utilization of a pasture were studied in wethers allowed a restricted time of access to forage. Twelve wethers housed in metabolic cages and fed fresh forage (predominantly Lotus corniculatus) ad libitum for 6 h/d were randomly assigned to one of the following treatments: a control forage without buffer (C) or a forage plus buffer composed of a mixture of 750 g/kg NaHCO₃ and 250 g/kg MgO at 20 g/kg dry matter intake (B). Feeding behaviour, feed and water intake and digestibility, urine output, Na urine elimination, kinetics of passage, ruminal pH and ammonia concentration, N balance and ruminal microbial N synthesis were determined in vivo, and the ruminal liquor activity was evaluated in vitro by fermentation of wheat straw. Addition of buffer increased total water intake (p = 0.05), Na urinary output (p = 0.01), purine derivative excretion in urine (p = 0.05) and tended to decrease mean total retention time in the digestive tract (p = 0.09). However, buffer addition increased ruminal pH (p < 0.001) and tended to decrease the ammonia concentration (p = 0.05). That use of buffer decreased ruminal activity was evidenced by a lower volume of gas produced in vitro (p = 0.01) possibly due to a lower microbial concentration in rumen liquor. The higher rumen dilution rate, likely due to a higher water intake, seems to have been the key driver of the actions of buffer supplementation on the rumen environment. Moreover, addition of NaHCO₃ led to an increased urinary Na excretion, which should be considered due to its likely negative environmental impacts.     

Effects of a blend of garlic oil,nitrate and fumarate on in vitro ruminal fermentation and microbial population

Although garlic oil and nitrate can effectively suppress ruminal methane (CH₄) production in vitro, the application of these compounds is associated with suppressed total volatile fatty acid (VFA) concentration. On the other hand, the effectiveness of fumarate as a ruminal CH₄ mitigating agent is variable but its application increases total VFA concentration. We therefore hypothesized that the different characteristics of the compounds can compensate for the shortcomings of the other. The objective of this study was to develop an optimal blend of garlic oil, nitrate and fumarate that can suppress in vitro ruminal CH₄ without affecting total VFA concentration. Three ruminal in vitro fermentation experiments were carried out. The first one, a one factor at a time experiment was employed to investigate the effective concentration of each of the compounds on CH₄ and VFA production by ruminal bacteria. We then applied the fractional factorial design and response surface methodology in the second experiment to determine optimal concentrations of the compounds in the blend. The optimal blending of garlic oil, fumarate and nitrate was determined to be 50 mg/l, 15 mm and 20 mm , respectively. This simulated optimal blend was verified in a 48 h in vitro batch fermentation experiment. The blend achieved the intended goal of suppressing CH₄ whilst maintaining total VFA concentration. The blend and nitrate suppressed archaea populations (p < 0.001) but did not affect the total microbial population (p = 0.945). The observed results could be explained by additive effects of the agents making up the blend. Supplementing a high concentrate diet with the blend can significantly decrease ruminal CH₄ and maintain total VFAin vitro. These findings however, need to be verified in vivo using the optimized ratio of combining the three methane inhibitors as a guide.     

Effect of wood kraft pulp feed on digestibility,ruminal characteristics,and milk production performance in lactating dairy cows

The effect of wood kraft pulp (KP) feed on dietary digestibility, ruminal fluid pH, rumen fermentation characteristics, and milk production performance in lactating dairy cows was examined. Four lactating dairy cows were used for the feeding experiment by the cross‐over design. The control group and KP group were set up as treatments. The control group was fed total mixed ration (TMR) (40% roughage and 60% concentrate) and the KP group was fed TMR containing 12% KP that replaced half of the rolled corn in the control diet. The dry matter intake, digestibility of the feed components, and milk yield were not significantly different between control group and KP group. The number of times that the ruminal fluid pH was below 6.1 tended to decrease in the KP group compared to the control group (p < 0.10). The acetic acid ratio in the ruminal fluid of the KP group increased compared to the control group (p < 0.05) and the propionic acid ratio in the ruminal fluid of the KP group decreased compared to the control group (p < 0.05). The acetate:propionate acid ratio was increased in the KP group compared with the control group (p < 0.05). Lipopolysaccharide levels in the ruminal fluid of the KP group tended to decrease compared to the control group (p < 0.10). Based on these results, it was indicated that the use of KP feed for lactating dairy cows induced the same rumen fermentation characteristics as those in cows given a large amount of roughage without depressing milk productivity. Therefore, KP could be a valuable feed resource substitute for grains, which would also reduce the risk for subacute rumen acidosis.     

Effects of substituting kraft pulp with corn silage on dry matter intake,ruminal mat formation,rumen fermentation,and rumination activity in non‐lactating cows

The present study examined the effects of substituting kraft pulp (KP) with corn silage (CS) on dry matter intake (DMI), ruminal mat and rumen fermentation characteristics, and rumination. Four non‐lactating, rumen‐cannulated Holstein cows were fed a CS diet comprising 36% grass silage (GS) and 64% CS or a KP diet comprising 36% GS, 57% KP, and 7% soybean meal. DMI was significantly lower in cows fed the KP diet than in those fed the CS diet (p < 0.05), whereas rumination time did not significantly differ between the treatments. Dry matter content in the rumen immediately before and 3 h after feeding was significantly higher in cows fed the KP diet than in those fed the CS diet (p < 0.05). The consistency and thickness of the ruminal mat did not significantly differ between the treatments. The ruminal mean retention time of feed particles tended to be longer in cows fed the KP diet than in those fed the CS diet (p < 0.10). The ruminal digestion rate of KP was comparable to that of GS and CS. Because ruminal mat was formed and rumination was stimulated, KP was considered to have the equivalent physical effectiveness as CS.     

Changes in in vitro ruminal and post‐ruminal degradation of tropical tannin‐rich legumes due to varying levels of polyethylene glycol

We evaluated the effects of tannins from Flemingia macrophylla (CIAT 17403) and Calliandra calothyrsus (San Ramón CIAT 22310 and Patulul CIAT 22316) on in vitro ruminal and post‐ruminal dry matter and apparent protein degradation. For each tannin source (legumes), different dosages of polyethylene glycol (PEG) (8000 Da) in McDougall buffer were added to achieve ratios of 0:3, 1:3, 2:3 and 3:3 PEG:condensed tannin (CT). Ruminal fluid mixed with McDougall buffer (1:4) was added to tubes containing only legume foliage (control) or PEG‐treated legume foliage. For both Calliandra varieties, a higher ruminal dry matter degradation was observed at a PEG:CT ratio of 3:3. For F. macrophylla, no differences were found between 2:3 and 3:3 ratios (p > 0.05), indicating that a PEG:CT ratio of 2:3 might be enough to bind tannins. Increasing PEG:CT ratios increased apparent ruminal degraded protein and ammonia concentration (p < 0.0001) differing among species (species × ratio: p < 0.0001). The degradation of bypass crude protein (dBCP) was influenced by both legume type and PEG:CT ratio (p < 0.0001). For Patulul, as PEG:CT ratio increased, dBCP increased, but after tannin ratio of 2:3, there was not a significant increase, and for San Ramón, dBCP degradation was higher as PEG:CT ratio increased up to 2:3. For Flemingia, dBCP was higher than PEG:CT ratio of 0:3 but not different among 1:3, 2:3 or 3:3. Low concentration of CT (116 mg/g DM) increased the proportion of protein digested in the abomasum, but higher levels of CT (252 mg/g) clearly reduced the proportion of digested CP. For Flemingia, PEG:CT ratio of 2:3 is enough to inactivate tannins, while PEG:CT ratio of 3:3 was needed for Calliandra and consequently increased ruminal degradation of dry mater (rdDM), and crude protein (rdCP), total degradation of dry matter (tdDM), crude protein (tdCP) and ammonia levels.     

Effects of different forms and origins of oilseeds on dynamics of ruminal biohydrogenation of long‐chain fatty acids in vitro

Dietary unsaturated fatty acids (FA) are intensively hydrogenated in the rumen, resulting in reduced amount of poly‐unsaturated fatty acids (PUFA) and accumulation of several biohydrogenation (BH) products. In this study, BH of PUFA originating from different oilseeds (linseed, soya beans, sunflower seed and rapeseed) present in crushed oilseeds or their free oils were assessed in vitro. The assay substrates were incubated in buffered rumen fluid for 0, 6, 12 and 24 h. After incubation, the FA pattern of the incubated samples was analysed using gas chromatography. Biohydrogenation is defined as disappearance of double bonds (DB) calculated from the contents of unsaturated FA. After 24‐h incubation, the DB contents of all oilseeds were reduced (p < 0.001) by 40–60%. The reduction was higher (p < 0.001) for the crushed form compared with the oil form. In addition, linseed and sunflower seed known as oilseeds with high contents of linolenic acid C18:3 c9,12,15 (LNA) and linoleic acid C18:2 c9,12 (LA), respectively, showed a higher (p < 0.001) accumulation of the BH intermediates conjugated linoleic acid (CLA, isomer C18:2 c9t11) and vaccenic acid (C18:1 t11) for the crushed form, when compared with the oil. These results suggest an inherent effect of the physical form of the assay oilseeds on in vitro BH. Changes in FA pattern during BH in vitro can be attributed to both source and physical form of the assay oilseeds. However, further investigations are warranted to ensure whether the observed in vitro effects on ruminal BH can be confirmed in vivo.     

Effect of dietary Schizochytrium microalga oil on selected markers of low‐grade inflammation in rats

The objective of the present study was to evaluate a potential of Schizochytrium microalga oil to alleviate possible negative effects of high‐fat‐high‐energy diets. Forty adult male rats (Wistar Albino) were fed 7 weeks the diet containing beef tallow + evaporated sweetened milk (diet T) intended to cause mild obesity and low‐grade systemic inflammation. Consequently, the animals were divided into four groups by 10 animals each and fed either the T‐diet (control) or the diet containing 6% of safflower oil (S), 6% of fish oil (F) and 6% of Schizochytrium microalga oil (A), respectively, for another 7 weeks. The A‐diet decreased (p < 0.05) live weight to 86% and glycaemia to 85% of control, respectively; an effect of the S‐ and F‐diet on these markers was insignificant (p > 0.05). In comparison with control, higher (p < 0.05) deposition of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) in the epididymal adipose tissue (EAT) of the A‐rats correlated with increased (p < 0.05) plasma adiponectin concentration, but it was without the effect (p > 0.05) on cellular adiponectin content in the EAT. Higher (p < 0.05) EPA+DHA deposition in the liver of the A‐rats correlated with higher expression (149% of control; p < 0.05) of the gene coding for peroxisome proliferator‐activated receptor gamma, and with lower expression (82% and 66%; p < 0.05) of the genes coding for adiponectin receptors AdipoR1 and AdipoR2; no relationship to the expression of receptor GPR120 was found. The A‐diet did not affect amount of the nuclear fraction of the nuclear factor kappa B in the liver, but increased plasma level of anti‐inflammatory cytokine TGF‐β1 (p < 0.05). The presented data agree with results of other in vivo rodent and human studies, but not with literature data regarding in vitro experiments: it can be concluded that the effects of dietary oils on inflammatory markers need further investigation.     

Effects of Antidesma thwaitesianum Muell. Arg. pomace as a source of plant secondary compounds on digestibility,rumen environment,hematology, and milk production in dairy cows

Mao pomace meal (MPM) contains condensed tannins and saponins at 92 and 98 g/kg, respectively, and these substances can be used to manipulate ruminal fermentation in ruminant. Four multiparous lactating Holstein cows with 45 ± 5 days in milk were randomly assigned according to a 4 × 4 Latin square design to receive four different levels of MPM supplementation at 0, 100, 200, and 300 g/head/day, respectively. Cows were fed with concentrate diets at 1:1.5 of concentrate to milk yield ratio and urea‐treated (3%) rice straw was fed ad libitum. The results revealed that feed intake, nutrient digestibility, blood urea nitrogen, and hematological parameters were not affected by MPM supplementation (p > 0.05). However, ruminal pH and propionate were increased quadratically (p < 0.05) in cows receiving MPM whereas acetate, acetate to propionate ratio and estimate methane production were decreased (p < 0.05). Supplementation of MPM linearly decreased ruminal ammonia nitrogen and protozoal population at 4 hr postfeeding (p < 0.05). Milk production and milk composition were similar among treatments (p > 0.05). In conclusion, supplementation of MPM at 200 g/head/day could modify ruminal fermentation and reduce methane production without adverse effect on feed intake, digestibility, hematological parameters, and milk production in dairy cows.     

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.     

Effects of feeding different levels of corn steep liquor on the performance of fattening lambs

This study was conducted to assess the effect of feeding corn steep liquor (CSL) on in vivo digestibility, ruminal pH, ammonia and hydrolytic enzyme activities, blood metabolites, feed intake (FI) and growth performance in fattening lambs. The CSL is a by‐product of wet milling process of maize starch industry. The crude protein (CP), rumen‐degradable protein (RDP), lactic acid and metabolisable energy contents of this by‐product were 420, 324, 200 g/kg dry matter (DM) and 12.6 MJ/kg DM respectively. Twenty‐seven male Moghani lambs were assigned randomly into three groups of nine lambs each in a completely randomised design. Three iso‐energetic and iso‐nitrogenous diets containing different levels (0, 50 or 100 g/kg dry matter) of CSL were offered ad libitum three times a day. Forage to concentrate ratio of the diets was 30:70. With inclusion of CSL in diet, the contents of canola meal, fish meal, wheat bran, corn grain and sugar beet pulp were decreased. The contents of DM, ash‐free neutral detergent fibre (NDFom), ether extract, starch, Ca and S were numerically lower, but soluble protein, RDP and non‐fibre carbohydrates were greater in the diets containing CSL in comparison with the control diet. The lambs fed with the diets containing CSL had lower [linear (L), p < 0.06] digestibility coefficients of DM and NDFom as compared to those fed with the diet free of CSL. Ruminal ammonia‐N concentration increased (L, p < 0.05), but pH decreased (L, p < 0.05) with raising CSL level in diet. Carboxymethyl cellulase and filter paper‐degrading activities decreased (L, p < 0.05), while proteases activity increased (L, p < 0.05) as dietary rates of CSL increased. Microcrystalline cellulase and ɑ‐amylase activities were similar among the treatments. Within blood metabolites, only urea‐N concentration increased (L, p < 0.05) in the lambs receiving CSL as compared to those fed with diet without CSL. Dietary inclusion of CSL resulted in linear decreases (L, p < 0.05) in the intakes of DM, organic matter, CP, NDFom and ash‐free acid detergent fibre, and average daily gain. However, the feed conversion ratio was similar among the experimental animals. Overall, feeding CSL up to 100 g/kg diet DM in lamb resulted in reductions of rumen fibrolytic microbial enzyme activities, in vivo digestibility, FI and growth performance, but rumen proteases activity increased.     

Effects of supplementary mother liquor,by‐product of monosodium glutamate,on in vitro ruminal fermentation characteristics

Mother liquor (ML) is monosodium glutamate by‐product and contains much crude protein (CP). The objective of this study was to investigate the effect of supplementation of two types of MLs having different chemical compositions on in vitro ruminal fermentation characteristics. ML1 had 74% organic matter (OM) and 70% CP and ML2 had 85% OM and 83% CP on a dry matter (DM) basis. The experiments were conducted using 0.5 gDM rolled barley or ryegrass straw as substrates. Urea and freeze‐dried MLs were added at three levels of nitrogen to be isonitrogenous. The ML1 treatment increased gas production compared with the ML2 treatment in barley substrate condition (p < 0.05). The supplementary ML2 increased gas production compared with the supplementary urea, and the digestibilities of DM and neutral detergent fiber expressed exclusive of residual ash (NDFom) were higher for the supplementary ML2 than for the supplementary ML1 in straw substrate condition (p < 0.05). In both the conditions, ammonia nitrogen concentrations of the ML1 and ML2 treatments were lower than that of the urea treatment (p < 0.05). The results indicated that the supplementary ML1 and ML2 activated in vitro ruminal fermentation particularly in concentrate and roughage substrate conditions respectively.     

Effect of ensiling whole crop oat with lucerne in different ratios on fermentation quality,aerobic stability and in vitro digestibility on the Tibetan plateau

The objective of this study was to determine the effect of ensiling different ratios of whole crop oat to lucerne on fermentation quality, aerobic stability and in vitro digestibility of silage on the Tibetan plateau. Four experimental treatments were produced varying in the ratio of forages on a fresh matter (FM) basis: 1) 100% oat (control, dry matter (DM) content: 317 g/kg), 2) 90% oat + 10% lucerne (OL10, DM content: 316 g/kg), 3) 80% oat+ 20% lucerne (OL20, DM content: 317 g/kg) and 4) 70% oat+ 30% lucerne (OL30, DM content: 318 g/kg). All treatments were packed into laboratory‐scale silos and ensiled for 60 days and then subjected to an aerobic stability test for 15 days. Further, the four experimental treatments were incubated in vitro with buffered rumen fluid to study the nutrient digestibility. All silages were well preserved with low pH and NH₃‐N contents, and high lactic acid contents and V‐scores (evaluation of silage quality). Increasing the lucerne proportion increased (p < 0.05) crude protein (CP) content of silage, whereas neutral (NDF) and acid (ADF) detergent fibre contents were not affected. Under aerobic conditions, the control silage showed higher (p < 0.05) yeast counts (>10⁵ cfu/g FM) followed by OL10 silage, and OL10 silage improved aerobic stability for 74 h. OL20 and OL30 silages showed fewer (p < 0.05) yeasts (<10⁵ cfu/g FM) and markedly (p < 0.05) improved the aerobic stability (>360 h). After 48‐h incubation, OL30 silage increased (p < 0.05) in vitro dry matter digestibility (IVDMD) and neutral detergent fibre digestibility (IVNDFD) compared with the control silage. These results suggest that replacing oat with lucerne had no unfavourable effects on fermentation quality of silage, but improved CP content, aerobic stability IVDMD and IVNDFD. OL30 silage was the best among the three mixed silages.     

Nigella sativa (black cumin seed) as a biological detoxifier in diet contaminated with aflatoxin B1

Aflatoxin B₁ (AFB₁) is a common feed contaminant that adversely affects bird performance and product quality. A total of 600 7‐day‐old quail chicks were randomly allotted to eight experimental groups in a completely randomized design with five replicate pens and 15 quails per pen. Experimental treatments including two levels of AFB₁ (0 and 2.5 mg/kg) and 4 levels of Nigella sativa (NS) (0, 0.5, 1.0 and 1.5% of diet) were offered from 7 to 35 days of age to quail chicks. Although feeding of AFB₁ impaired gain (G) and feed conversion ratio, dietary NS increased G (p < 0.05). Relative weight of bursa of Fabricius increased with incremental levels of NS (p < 0.05). AFB₁ decreased the size of heart, but incremental levels of NS increased the relative weight of heart (p < 0.05). The liver hypertrophy was observed in birds receiving AFB₁ (p < 0.05). The birds in AFB₁ group had smaller testes than other groups (p < 0.05). Hematocrit value in birds fed AFB₁ was lower than that in other groups (p < 0.05) and incremental levels of NS increased blood hematocrit (p < 0.05). Amount of malondialdehyde (MDA) in meat samples of the birds fed AFB₁ was higher than those did not receive toxin but incremental levels of NS decreased the MDA concentration in affected birds (p < 0.05). AFB₁ suppressed the humoral immunity of the birds while NS augmented the antibody titres against sheep red blood cell and Newcastle disease virus antigens (p < 0.05). AFB₁ decreased lactic acid bacteria (LAB) and spore‐forming bacteria (SFB) but increased Escherichia coli (E. coli; p < 0.05). However, NS increased LAB and SFB but decreased the E. coli populations (p < 0.05). This study revealed that NS as a biological detoxifier could relatively attenuate the negative effects of AFB₁ in quails.     

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.     

Methyl‐β‐Cyclodextrin Improves Sperm Capacitation Status Assessed by Flow Cytometry Analysis and Zona Pellucida‐Binding Ability of Frozen/Thawed Bovine Spermatozoa

Mammalian sperm undergo a series of biochemical transformations in the female reproductive tract that are collectively known as capacitation. Cyclodextrins added to the sperm culture medium have been described to induce in vitro sperm capacitation, enabling its use in protein‐free media. However, the additive capacitating effect of methyl‐β‐cyclodextrin (MβCD) in the medium containing bovine serum albumin (BSA) is unknown in the bovine species. In this study, we evaluated the effects of incubating frozen–thawed bovine spermatozoa in a BSA‐containing medium supplemented with MβCD on different sperm quality and functional parameters. Sperm viability decreased with the addition of MβCD in a dose‐dependent manner (p < 0.05), and DNA damage could be observed but only with the highest concentration of MβCD. However, pre‐incubation of spermatozoa in MβCD‐supplemented medium improved the capacitation status as assessed by the increase in plasma membrane fluidity, intracellular calcium concentration, induced acrosome reactivity and zona pellucida (ZP)‐binding ability (p < 0.05). Thus, we conclude that MβCD supplementation is able to enhance the capacitation status of frozen–thawed bovine spermatozoa cultured in capacitation medium containing BSA and could result in a valid strategy for its application on artificial reproductive technologies such as in vitro fertilization or intracytoplasmic sperm injection.     

Melatonin Supplementation During In Vitro Maturation and Development Supports the Development of Porcine Embryos

Melatonin has been reported to improve the in vitro development of embryos in some species. This study was conducted to investigate the effect of melatonin supplementation during in vitro maturation (IVM) and development culture on the development and quality of porcine embryos. In the first experiment, when the in vitro fertilized embryos were cultured with different concentrations of melatonin (0, 10, 25 and 50 ng/ml) for 8 days, the blastocyst formation rate of embryos cultured with 25 ng/ml melatonin (10.7%) was significantly increased (p < 0.05) compared to the control embryos cultured without melatonin (4.2%). The proportion of DNA‐fragmented nuclei in blastocysts derived from embryos cultured with 50 ng/ml melatonin was significantly lower (p < 0.05) than that of embryos cultured without melatonin (2.1% vs 7.2%). In the second experiment, when oocytes were cultured in the maturation medium supplemented with different concentrations of melatonin (0, 10, 25 and 50 ng/ml), fertilized and then cultured with 25 ng/ml melatonin for 8 days, there were no significant differences in the rates of cleavage and blastocyst formation among the groups. However, the proportions (2.7–5.4%) of DNA‐fragmented nuclei in blastocysts derived from oocytes matured with melatonin were significantly decreased (p < 0.05) compared to those (8.9%) from oocytes matured without melatonin, irrespective of the concentration of melatonin. Our results suggest that supplementation of the culture media with melatonin (25 ng/ml) during IVM and development has beneficial effects on the developmental competence and quality of porcine embryos.     

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.     

Modulation of ruminal and intestinal fermentation by medicinal plants and zinc from different sources

Two experiments were conducted on sheep to determine the effect of dietary supplementation with zinc and a medicinal plant mixture on haematological parameters and microbial activity in the rumen and large intestine. In Experiment 1, 24 male lambs were randomly divided into four groups: One group was fed an unsupplemented basal diet (control), and three groups were fed a diet supplemented with 70 mg Zn/kg diet in the form of Zn sulphate (ZnSO₄), a Zn‐chelate of glycine hydrate (Zn‐Gly) or a Zn‐proteinate (Zn‐Pro), for five months. The ruminal content was collected separately from each lamb, and batch cultures of ruminal fluid were incubated in vitro with mixture of medicinal plants (Mix) with different roughage:concentrate ratios (800:200 and 400:600, w/w). Bioactive compounds in Mix were quantified by UPLC/MS/MS. In Experiment 2, four sheep were fed a diet consisting of meadow hay and barley grain (400:600, w/w), with Zn‐Gly (70 mg Zn/kg diet), Mix (10% replacement of meadow hay) or Zn‐Gly and Mix (Zn‐Gly‐Mix) as supplements in a Latin square design. Mix decreased total gas (p < 0.001) and methane (p < 0.01) production in vitro. In Experiment 1, caecal isobutyrate and isovalerate concentrations varied among the dietary treatments (p < 0.01). The isovalerate concentration of the zinc‐supplemented groups in the distal colon was higher (p < 0.001) compared with the control. In Experiment 2, the molar proportion of isobutyrate was the highest in the faeces of the sheep fed the diet with Zn‐Gly‐Mix (p < 0.01). The plasma zinc concentration was higher in the groups fed a diet supplemented with zinc (p < 0.001). The haematological profile and antioxidant status did not differ between the dietary groups (p > 0.05). The diets containing medicinal plants and organic zinc thus helped to modulate the characteristics of fermentation in ruminants.