Investigations of the treatment of sawdust for rabbit feeding. 1. Effect of sodium hydroxide treatment

A total of one hundred and eighty-four New Zealand White rabbits were used in three separate experiments: to establish the concentration of sodium hydroxide solution needed to improve the nutritive quality of sawdust for rabbit feeding; to investigate whether there is any difference between the nutritive quality of hardwood- or softwood-sawdust when treated with optimum sodium hydroxide solution; and to study the extent to which NaOH-treated sawdust can be substituted for the conventional feeds in rabbit diets.Food consumption was significantly (P < 0.05) greater in rabbits given diets containing sawdust treated with 6% solutions of NaOH, than with sawdust treated with 0–3% solutions. Rabbits given sawdust treated with 4 or 5% NaOH showed significantly (P < 0.05) better rate of gain and efficiency of feed utilization than those given sawdust treated with 0 or 1% sodium hydroxide solutions, and also grew slightly, but non-significantly, faster than those fed on sawdust treated with 3 and 6% NaOH.Alkali treatment of sawdust increased carcass yield. Hardwood-responded better than softwood-sawdust to alkali treatment, and a higher concentration of alkali may be required for the latter. Rabbits may tolerate and efficiently utilize up to 15% of treated sawdust without any reduction in performance. Beyond this level, there was a significant (P < 0.05) decrease in the rate of gain, feed/gain ratio and carcass yield.     

Modification of wheat straw lignin by solid state fermentation with white-rot fungi

The potential of crude enzyme extracts, obtained from solid state cultivation of four white-rot fungi (Trametes versicolor, Bjerkandera adusta, Ganoderma applanatum and Phlebia rufa), was exploited to modify wheat straw cell wall. At different fermentation times, manganese-dependent peroxidase (MnP), lignin peroxidase (LiP), laccase, carboxymethylcellulase (CMCase), avicelase, xylanase and feruloyl esterase activities were screened and the content of lignin as well as hydroxycinnamic acids in fermented straw were determined. All fungi secreted feruloyl esterase while LiP was only detected in crude extracts from B. adusta. Since no significant differences (P > 0.05) were observed in remaining lignin content of fermented straw, LiP activity was not a limiting factor of enzymatic lignin removal process. The levels of esterified hydroxycinnamic acids degradation were considerably higher than previous reports with lignocellulosic biomass. The data show that P. rufa, may be considered for more specific studies as higher ferulic and p-coumaric acids degradation was observed for earlier incubation times.     

The feeding value of ammoniated flax straw,wheat straw and wheat chaff for beef cattle

Two experiments were conducted to assess the feeding value of ammoniated and untreated flax straw, wheat straw and wheat chaff in comparison to a mixed bromegrass/alfalfa hay. Anhydrous ammonia was applied to the crop residues at the rate of 35 kg t⁻¹ dry matter. In the first experiment, the effect of ammoniation on crude protein, acid detergent fibre (ADF), neutral detergent fibre (NDF) and acid detergent lignin (ADL), digestible organic matter in vitro and in vivo (DOM%), ADF and NDF digestibility of the crop residues was determined. In the second experiment, ammoniated flax straw, ammoniated wheat straw, ammoniated and untreated wheat chaff, each supplemented with barley, were compared to bromegrass/alfalfa hay as feed sources for wintering beef cows.Ammoniation increased the crude protein content of the crop residues ∼2-fold. Wheat straw DOM in vitro and in vivo was not increased by ammoniation. Ammoniation increased the DOM in vitro of wheat chaff from 36.3 to 46% and flax straw from 35.2 to 46.3%. The DOM in vivo increased from 53.3 to 63.4% (P < 0.05) for wheat chaff and from 33.9 to 58.4% (P < 0.05) for flax straw following ammoniation. Digestibility of ADF increased from 9.9 to 43.9% (P < 0.05) and of NDF from −0.6 to 37.9% (P < 0.05) in flax straw with ammoniation. Non-significant increases in ADF and NDF digestibility were observed for all other crop residues. Lignin content was not changed in the crop residues by ammoniation.In the winter feeding trial, young cows gained more weight than older cows (P < 0.05). Average daily gains of cows were greatest for hay followed by ammoniated flax straw, ammoniated chaff, untreated chaff and ammoniated wheat straw rations (P < 0.05). Increases in backfat in the younger cows was greatest with hay and ammoniated flax straw, followed by ammoniated chaff and ammoniated wheat straw (P < 0.05). Untreated chaff caused no increase in backfat thickness.Ammoniated flax straw (3.2 kg day⁻¹) given with barley (5.6 kg day⁻¹), is similar in feeding value to medium quality bromegrass/alfalfa hay. Furthermore, wheat chaff and ammoniated wheat chaff show good potential as alternatives to hay in winter feeding.     

The effect of rabbit age on in vitro caecal fermentation of starch, pectin, xylan, cellulose, compound feed and its fibre

In vitro gas production kinetics of six different substrates, pectin (PEC), xylan (XYL), starch (STA), cellulose (CEL), commercial compound feed (FEED; 201 g crude protein per kg, 155 g crude fibre per kg, 334 g neutral-detergent fibre (NDF) per kg and 190 g acid-detergent fibre (ADF) per kg) and an NDF prepared from commercial compound feed (NDF_FEED) were determined using the caecum contents of weaned rabbits (36 days of age) and of rabbits at slaughter age (78 days of age) as inoculums. The cumulated gas production over 96 h of incubation was modelled with Gompertz model, and the kinetic parameters compared. The total potential gas production (parameter ‘B’ of the Gompertz model) was not affected (P>0.05) by the inoculum source, except with STA, where rabbits at slaughter weight had significantly higher total potential fermentability (314 ml/g dry matter (DM)) than those at weaning age (189 ml/g DM). Intensities of fermentation (maximum fermentation rate; MFR) of PEC (32.2 ml/h) and XYL (24.4 ml/h) were significantly greater in rabbits at weaning, while that of STA (45 ml/h) was significantly lower than at slaughter age (23.0, 14.3 and 14.0 ml/h for PEC, XYL and STA, respectively). The MFRs of CEL and NDF_FEED were very similar between inoculum sources. In the first 10 h of fermentation which correspond to the normal retention time of the substrates in the caecum, the highest amount of gas was produced from PEC, followed by FEED and XYL. These substrates had a time of maximum fermentation rate (TMFR) at both rabbit ages short enough (8.0 and 9.5 h for PEC, 9.5 and 6.6 h for FEED, 13.7 and 14.2 h for XYL at weaning and at slaughter age, respectively) to be almost completely fermented in vivo.     

Fermentation characteristics and feeding value of ensiled poultry litter containing wheat straw,bagasse or sawdust

Poultry excreta substantially increased the crude protein (CP) content and the calcium and phosporus content of the base bedding materials. The crude fibre (CF) content of sawdust (52.3%) was higher than that of wheat straw (38.9%) and bagasse (30.2%). Dry matter digestibility in vitro (IVDMD) of wheat straw, bagasse and sawdust poultry litters (PL) was 65.4, 64.5 and 48.1%, respectively. Green sorghum fodder when ensiled alone or with 20% wheat straw PL, sawdust PL or bagasse PL on fresh basis contained 4.67, 7.80, 10.00 and 7.55% CP, respectively. Nitrogen-free extract (NFE) content of PL silages was lower than that of the control. Apart from wheat straw PL, all silages accumulated considerable amounts of lactic acid. The total volatile fatty acids (TVFA) concentrations were similar for all silages. The addition of PL caused an increase in the proportion of ammonia nitrogen. A feeding trial with crossbred adult male cattle revealed no significant difference in dry matter (DM), CP and ether extract (EE) digestibility of wheat straw and bagasse PL silages. The CF digestibility was similar for all the silages. Sawdust PL silage, however, was significantly lower (P < 0.05) in digestibility of DM, EE and NFE compared to other PL based silages. The DCP and TDN values for the control, wheat straw, bagasse and sawdust PL silages were 2.0, 60.1; 4.3, 45.3; 6.1, 50.3 and 2.9, 41.9 kg/100 kg DM, respectively.     

A rapid fibre method for discriminating between high and low energy sorghum grain for poultry

Twenty-seven samples of sorghum grain of known metabolizable energy content for poultry were extracted with 3% lauryl sulphate in 0.1N HCl. Metabolizable energy was predicted from the fibre remaining from this extraction procedure with a precision of ± 0.57 MJ/kg dry matter, corresponding to a coefficient of variation of ± 3.5%. This degree of precision was similar to that for crude fibre, acid-detergent fibre and total fibre determined previously on these grain samples. The total time for analysis was 45 min for a single sample, or 60 min for the simultaneous analysis of six samples.     

Digestibility of diets containing increasing levels of NaOH-treated or untreated wheat straw

Sodium hydroxide-treated or untreated wheat straw was included in a basal alfalfamaize diet at 0, 10, 20 and 40%. As the level of straw increased, the apparent digestibility of dry matter (DM) and organic matter (OM) by sheep, decreased linearly (P < 0.01), with a faster decrease (P < 0.05) for diets containing untreated straw. The digestibility of DM decreased by 0.22 and 0.41% and OM by 0.24 and 0.42% for treated and untreated straw diets, respectively, with each 1% increase of straw in the diets.Addition of treated straw increased (P < 0.05) digestibility of cell wall constituents (CWC), acid detergent fibre (ADF) and hemicellulose (HC). However, when untreated straw was added, the digestibility of HC was reduced, whereas the digestibility of CWC and ADF was dependent on the level of straw added. Increasing levels of NaOH-treated straw in the diets produced linear increases (P < 0.05) in digestibility of CWC, ADF and HC. However, significant (P < 0.05) linear or quadratic responses were not noted in the digestibility of CWC, ADF and HC with increasing levels of untreated straw in the diet. Apparent digestibility of crude protein was not affected by addition of either NaOH-treated or untreated straw to the diet.In general, although changes in nutrient digestibility of the basal component small, large changes in the digestibility of nutrients in the straw component were apparent and accounted for the major differences in digestibility of the diets. The absence of curvilinearity in the regression equations suggested that there were no associative effects.     

White-rot fungal conversion of wheat straw to energy rich cattle feed

In order to improve the digestibility and nutrient availability in rumen, wheat straw was subjected to solid state fermentation (SSF) with white-rot fungi (i.e. Pleurotus ostreatus and Trametes versicolor) and the fermented biomass (called myco-straw) was evaluated for biochemical, enzymatic and nutritional parameters. The fungal treatment after 30 days led to significant decrease (P < 0.05) in cell wall constituents viz, acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, lignin and cellulose to the extent of 35.00, 38.88, 45.00, 37.48 and 37.86%, respectively in P. ostreatus fermented straw, while 30.04, 33.85, 39.90, 31.29 and 34.00%, respectively in T. versicolor fermented straw. However, maximum efficiency of fermentation in terms of low carbohydrate consumption per unit of lignin degradation, favoring cattle feed production was observed for P. ostreatus on the 10th day (17.12%) as compared with T. versicolor on the 30th day (16.91%). The myco-straw was found to contain significantly high (P < 0.05) crude protein (CP; 4.77% T. versicolor, 5.08% P. ostreatus) as compared to control straw (3.37%). Metabolizable energy (ME, MJ/kg DM), percent organic matter digestibility (OMD) and short chain fatty acids (SCFAs; mmol) production also increased considerably from control straw (4.40, 29.91 and 0.292) to a maximum up to P. ostreatus fermented straw (4.92, 33.39 and 0.376 on 20th day) and T. versicolor fermented straw (4.66, 31.74 and 0.334 on 10th day), respectively. Moreover, the myco-straw had lower organic carbon and was rich in nitrogen with lower C/N ratio as compared to control wheat straw. Results suggest that the fungal fermentation of wheat straw effectively improved CP content, OM digestibility, SCFAs production, ME value and simultaneously lowered the C/N ratio, thus showing potential for bioconversion of lignin rich wheat straw into high energy cattle feed.     

The impacts of fermented feed on laying performance,egg quality,immune function,intestinal morphology and microbiota of laying hens in the late laying cycle

Fermented feed has the potential to improve poultry gastrointestinal microecological environment, health condition and production performance. Thus, the present study was undertaken to explore the effects of fermented feed on the laying performance, egg quality, immune function, intestinal morphology and microbiota of laying hens in the late laying cycle. A total of 360 healthy Hy-Line Brown laying hens aged 80 weeks were used to conduct a 56-day study. All hens were randomly separated into two treatment groups, with five replicates of 36 hens each as follows: basal diet containing 0.0% fermented feed (CON) and 20% fermented feed (FF). Subsequent analyses revealed that fermented feed supplementation was associated with significant increases in laying rates together with reduced broken egg rates and feed conversion ratio for hens in FF group (P < 0.05). There were additionally significant increases in both albumen height and Haugh unit values in hens following fermented feed supplementation (P < 0.05). Fermented feed was also associated with increases in duodenal, jejunal and ileac villus height (P < 0.05). Laying hens fed fermented feed had higher immune globulin (Ig)A, IgG, IgM levels (P < 0.01,) and higher interleukin 2, interleukin 6, tumour necrosis factor α and interferon γ (P < 0.05) concentrations than CON. Analysis of the microbiota in these laying hens revealed the alpha diversity was not significantly affected by fermented feed supplementation. Firmicutes abundance was reduced in caecal samples from FF hens relative to those from CON hens (30.61 vs 35.12%, P < 0.05). At the genus level, fermented feed was associated with improvements in relative Lactobacillus, Megasphaera and Peptococcus abundance and decreased Campylobacter abundance in laying hens. These results suggest that fermented feed supplementation may be beneficial to the laying performance, egg quality, immunological function, intestinal villus growth and caecal microecological environment of laying hens at the end of the laying cycle.     

Response of Plant Parasitic and Free Living Soil Nematodes to Composted Animal Manure Soil Amendments

In an outside pot experiment, dry pig manure processed on pine sawdust litter and fermented for seven days by house fly larvae (fermented manure), and pine sawdust applied alone, and in combination with a spring application of inorganic nitrogen fertilizer were used to determine their effects on plant parasitic and free-living soil nematodes on sugar beets (cv. Antek). Non amended soil was used as a control. All treatments with fermented pig manure and sawdust with nitrogen fertilizer decreased number of plant parasitic nematodes and also root-fungal feeding nematodes compared to the untreated control. Sawdust applied alone had no effect on plant parasitic and root-fungal feeding nematode suppression. Free-living nematodes which were mainly bacteriovores and fungivores were significantly more abundant in soil amended with fermented pig manure, while the sawdust had no effect on these nematodes. The effect of all tested treatments on omnivores-predators was rather random, and in general, the number of these nematodes decreased after soil amendment applications compared to the untreated control.     

Growth of Chaetomium cellulolyticum on Alkali-Pretreated Hardwood Sawdust Solids and Pretreatment Liquor

The treatment of a hardwood sawdust with 1% NaOH solution at 121°C dissolved 19.7% of the dry matter, mainly hemicellulose and lignin. Fermentation of the treated solids by Chaetomium cellulolyticum for 48 h gave a product containing 12.5% crude protein (total N × 6.25) on a dry weight basis. The in vitro rumen digestibility of the 48-h fermentation product was 30%, compared to 24% for the alkali-treated but unfermented sawdust. Growth was independent of sawdust particle size in the range 40 to 100 mesh. Fermentation of the pretreatment liquor gave a product containing up to 50% crude protein (dry weight basis) with an in vitro rumen digestibility of 65 to 76%. Approximately 6.7 g of crude protein was obtained from the treated solids and 2.2 g from the pretreatment liquor per 100 g of sawdust treated. The product from the pretreatment liquor fermentation has potential as a high-protein animal feed supplement but could not be produced economically without an outlet for the relatively indigestible product from the solids fermentation. Growth on the pretreatment liquor was strongly pH dependent; there was a considerable increase in the lag phase when the pH was lowered from 7.5 to 5.2. This effect appears to be due to an inhibitor whose toxicity is reduced at high pH.     

Reducing agent can be omitted in the incubation medium of the batch in vitro fermentation model of the pig intestines

Over the past decade, in vitro methods have been developed to study intestinal fermentation in pigs and its influence on the digestive physiology and health. In these methods, ingredients are fermented by a bacterial inoculum diluted in a mineral buffer solution. Generally, a reducing agent such as Na₂S or cysteine-HCl generates the required anaerobic environment by releasing metabolites similar to those produced when protein is fermented, possibly inducing a dysbiosis. An experiment was conducted to study the impact of two reducing agents on results yielded by such in vitro fermentation models. Protein (soybean proteins, casein) and carbohydrate (potato starch, cellulose) ingredients were fermented in vitro by bacteria isolated from fresh feces obtained from three sows in three carbonate-based incubation media differing in reducing agent: (i) Na₂S, (ii) cysteine-HCl and (iii) control with a mere saturation with CO₂ and devoid of reducing agent. The gas production during fermentation was recorded over 72 h. Short-chain fatty acids (SCFA) production after 24 and 72 h and microbial composition of the fermentation broth after 24 h were compared between ingredients and between reducing agents. The fermentation residues after 24 h were also evaluated in terms of cytotoxicity using Caco-2 cell monolayers. Results showed that the effect of the ingredient induced higher differences than the reducing agent. Among the latter, cysteine-HCl induced the strongest differences compared with the control, whereas Na₂S was similar to the control for most parameters. For all ingredients, final gas produced per g of substrate was similar (P>0.10) for the three reducing agents whereas the maximum rate of gas production (R_max) was reduced (P<0.05) when carbohydrate ingredients were fermented with cysteine-HCl in comparison to Na₂S and the control. For all ingredients, total SCFA production was similar (P>0.10) after 24 h of fermentation with Na₂S and in the control without reducing agent. Molar ratios of branched chain-fatty acids were higher (P<0.05) for protein (36.5% and 9.7% for casein and soybean proteins, respectively) than for carbohydrate (<4%) ingredients. Only fermentation residues of casein showed a possible cytotoxic effect regardless of the reducing agent (P<0.05). Concerning the microbial composition of the fermentation broth, most significant differences in phyla and in genera ascribable to the reducing agent were found with potato starch and casein. In conclusion, saturating the incubation media with CO₂ seems sufficient to generate a suitable anaerobic environment for intestinal microbes and the use of a reducing agent can be omitted.     

A comparison of three fibre methods for predicting the metabolizable energy content of sorghum grain for poultry

An apparatus designed to simplify analytical procedures for determining fibre in food was used to measure fibre of similar composition to crude fibre, acid-detergent fibre and neutral-detergent fibre in 27 samples of sorghum grain. The metabolizable energy content of these grains for poultry was predicted from the three fibre methods with precision, respectively, of ± 0.49, ± 0.62 and ± 0.53 MJ/kg dry matter. These values corresponded to coefficients of variation of ± 3.0, ± 3.8 and ± 3.3%.The three fibre fractions were highly correlated with each other, and so a simple method that can measure a part of the total fibre is suitable for predicting the energy value of sorghum grain for poultry.     

In vitro digestion and fermentation characteristics of canola co-products simulate their digestion in the pig intestine

Canola co-products are sources of amino acid and energy in pig feeds, but their fermentation characteristics in the pig intestine are unknown. Thus, we determined the in vitro fermentation characteristics of the canola co-products Brassica juncea solvent-extracted canola meal (JSECM), Brassica napus solvent-extracted canola meal (NSECM), B. napus expeller-pressed canola meal (NEPCM) and B. napus cold-pressed canola cake (NCPCC) in comparison with soybean meal (SBM). Samples were hydrolysed in two steps using pepsin and pancreatin. Subsequently, residues were incubated in a buffer solution with fresh pig faeces as inocula for 72 h to measure gas production. Concentration of volatile fatty acids (VFA) per gram of dry matter (DM) of feedstuff was measured in fermented solutions. Apparent ileal digestibility (AID) and apparent hindgut fermentation (AHF) of gross energy (GE) for feedstuffs were obtained from pigs fed the same feedstuffs. On DM basis, SBM, JSECM, NSECM, NEPCM and NCPCC contained 15, 19, 22, 117 and 231 g/kg ether extract; and 85, 223, 306, 208 and 176 g/kg NDF, respectively. In vitro digestibility of DM (IVDDM) of SBM (82.3%) was greater (P<0.05) than that of JSECM (68.5%), NSECM (63.4%), NEPCM (67.5%) or NCPCC (69.8%). The JSECM had greater (P<0.05) IVDDM than NSECM. The IVDDM for NSECM was lower (P<0.05) than that for NEPCM, which was lower (P<0.05) than that for NCPCC. Similarly, AID of GE was greatest for SBM followed by NCPCC, JSECM, NEPCM and then NSECM. Total VFA production for SBM (0.73 mmol/g) was lower (P<0.05) than that of JSECM (1.38 mmol/g) or NSECM (1.05 mmol/g), but not different from that of NEPCM (0.80 mmol/g) and NCPCC (0.62 mmol/g). Total VFA production of JSECM was greater (P<0.05) than that of NSECM. Total VFA production of NSECM was greater (P<0.05) than that of NEPCM or NCPCC, which differed (P<0.05). The ranking of feedstuffs for total VFA production was similar to AHF of GE. In conclusion, in vitro fermentation characteristics of canola co-products and SBM simulated their fermentation in the small and large intestine of pigs, respectively. The 30% greater VFA production for JSECM than NSECM due to lower lignified fibre of JSECM indicates that fermentation characteristics differ between canola species. The NSECM had the highest fermentability followed by NEPCM and then NCPCC, indicating that fat in canola co-products can limit their fermentability in the hindgut.     

The effect of dietary molybdenum supplementation on tissue copper concentrations,mohair fibre and carcass characteristics of growing Angora goats

The purpose of this experiment was to better characterize the effects of the interaction between copper (Cu), molybdenum (Mo) and sulphur (S) in the diet on growth, metabolism and fibre characteristics in Angora goats. 15 Angora goats aged 9 months and weighing 21.5 kg on average were used in a ten-week study and allocated to three dietary treatments: Treatment C (10 MJ metabolisable energy, 178 g crude protein, 5.5 mg Cu, 0.57 mg Mo, and 3.4 g S): Treatment M1 (with 7.5 mg Mo) or Treatment M2 (with 15 mg Mo) per animal per day. Dose-dependent increases in the concentrations of Mo (P < 0.01) and Cu (P < 0.05) in plasma were recorded in response to increased dietary intake of Mo. Supplementation of the control diet with increased concentrations of Mo did not produce effects (P > 0.05) on growth rate, feed conversion efficiency, carcass weight or mohair fibre yield and diameter.Haematological status and concentration of Cu in liver and Cu and S in fibre at the end of the study were also not affected (P > 0.05).Concentrations of trichloroacetic acid (TCA) soluble “available” copper in plasma were not significantly different although significant (P < 0.05 and P < 0.01) reductions in the ratio of “available” to total Cu concentrations were observed. This effect was stabilised and maintained after 30 days. It is suggested that the additional Cu in plasma was largely TCA insoluble and possibly in the form of thiomolybdate complexes which may be poorly excreted and not available for uptake to the metabolic sites. It is evident that adequate “available” Cu was present in plasma and that exposure to elevated Mo intake was not severe or long enough to produce clinical symptoms or to affect growth, haematological status or fibre production.     

Evaluation of Nutritive Value of Raw and Fermented De-oiled Physic Nut, Jatropha curcas Seed Meal in the Formulated Diets for Rohu, Labeo rohita (Hamilton) Fingerlings

Rohu (Labeo rohita) fingerlings, were fed de-oiled Jatropha curcas seed meal (DJSM) supplemented diets for 60 days and the effectiveness, if any, on the growth was evaluated. Nine isonitrogenous (35 % crude protein) and isocaloric (4.0 kcal g^?1) diets were formulated of which one was reference diet (RD, fishmeal based control diet) and the other eight were experimental diets prepared by incorporating raw (D1–D4) and fermented (D5–D8) DJSM at 10, 20, 30 and 40 % levels by weight, respectively. Autoclaved DJSM was processed through solid state fermentation (SSF) for 15 days at 37 ± 1 °C by an exo-enzyme producing bacterium, Bacillus cereus Lr.H.23 isolated from the hindgut of rohu, L. rohita. Processing through SSF caused decrease in the contents of crude fibre and anti-nutritional factors, but increase in the levels of free amino acids and free fatty acids. In terms of growth performance, feed utilization efficiency and apparent protein digestibility, fish fed diet D7 containing 30 % fermented DJSM showed the best performance, which differed significantly (P < 0.05) from that of the fish fed diets containing raw DJSM. The results indicated that an inclusion level up to 30 % fermented DJSM replacing 15 % FM in the practical diet for rohu fingerlings can be proposed when compared to the RD. However, further experiments are required to recommend the ingredient for use in industry.     

Changes of chemical and nutrient composition of porcine blood during fermentation by <Emphasis Type="Italic">Aspergillus oryzae</Emphasis>

A solid-state fermentation (SSF) of a mixture of porcine blood and wheat bran with a ratio of 8:1 by Aspergillus oryzae was investigated. Water content, pH, crude protein, heme and total iron, free amino acids (FAA) and total fatty acids (TFA) of the fermented mixture were determined at 0, 40, 80 and 120 h, respectively, and protein hydrolysis were analyzed with SDS-PAGE accordingly. The results showed that, during the fermentation, water contents and pH decreased significantly (P < 0.05) from 68.33% to 59.94%, 7.18% to 4.48%, respectively. Heme iron content changed slightly (P > 0.05). With the degradation of large protein molecules, free amino acids in the mixture increased from 872.83 mg l⁻¹ to 11560.94 mg l⁻¹ (P < 0.05). Content of free isoleucine, methionine and cystine, deficient in fresh porcine blood increased (P < 0.05) after fermentation. Percentages of saturated fatty acids such as C14:0, C17:0 and C18:0 in the total fatty acids decreased significantly (P < 0.05), and those of polyunsaturated fatty acids C18:1, C18:2, C18:3, C20:1 and C20:2 increased significantly from 27.06% to 47.90% (P < 0.05). The results indicated that Aspergillus oryzae could ferment porcine blood and bran mixture and change its chemical and nutrient composition.     

Effects of soluble fiber inclusion in gestation diets with varying fermentation characteristics on lactational feed intake of sows over two successive parities

The effects of soluble fiber inclusion in gestation diets with varying fermentation characteristics (fermentation kinetics and short-chain fatty acids (SCFA)-profile) on lactational feed intake of sows and their piglet growth over two parities were investigated using an in vitro–in vivo methodology. After breeding, 90 multiparous Landrace sows were randomized to one of three experimental diets: the control (CON) diet, konjac flour (KF) diet or sugar beet pulp (SBP) diet. All diets had similar levels of net energy, CP, insoluble fiber and NDF, but KF and SBP diets had higher soluble fiber levels than the CON diet. During gestation, the sows were restrictively fed with three different diets, but during lactation, all the sows were similarly fed ad libitum. The three gestation diets were enzymatically hydrolyzed using pepsin and pancreatin, and enzymolyzed residues were used in in vitro fermentation. Gas and SCFA production were monitored during fermentation. After fermentation, enzymolyzed residues of KF or SBP diets resulted in higher final asymptotic gas volume than those of the CON diet. The enzymolyzed residues of KF diet were mainly part of rapidly fermented fractions, whereas those of SBP diet were mainly part of slowly fermented fractions. In addition, the acetic acid, butyric acid and total SCFA concentrations of enzymolyzed residues of KF diet were higher (P<0.01) than the control and SBP diets. In the in vivo studies, on day 90 of gestation, the KF diet sows had higher plasma SCFA concentration (P<0.05) at 4 h after feeding than the CON diet sows. Furthermore, the KF diet sows had lower plasma free fatty acid (FFA) concentration (P<0.01) at 4 h after feeding, and a lower value of homeostasis model assessment (HOMA)-insulin resistance (P<0.05), but a higher value of HOMA-insulin sensitivity (P<0.01). The KF diet sows also consumed more feed during lactation (P<0.01) and weaned significantly heavier pigs (P<0.01) than the CON diet sows. The overall results showed that the high fermentation capacity KF diet contributed to an increased lactational feed intake and improved performance of piglets in the second reproductive cycle.     

Effect of whole-plant corn silage treated with lignocellulose-degrading bacteria on growth performance,rumen fermentation,and rumen microflora in sheep

Lignification of cellulose limits the effective utilisation of fibre in plant cell wall. Lignocellulose-degrading bacteria secrete enzymes that decompose lignin and have the potential to improve fibre digestibility. Therefore, this study aimed to investigate the effect of whole-plant corn silage inoculated with lignocellulose-degrading bacteria on the growth performance, rumen fermentation, and rumen microbiome in sheep. Twelve 2-month-old male hybrid sheep (Dorper ♂ × small-tailed Han ♀) were randomly assigned into two dietary groups (n = 6): (1) untreated whole-plant corn silage (WPCS) and (2) WPCS inoculated with bacterial inoculant (WPCSB). Whole-plant corn silage inoculated with bacterial inoculant had higher in situ NDF digestibility than WPCS. Sheep in the WPCSB group had significantly higher average daily gain, DM intake, and feed conversion rate than those in the WPCS group (P < 0.05). Furthermore, higher volatile fatty acid concentrations were detected in WPCSB rumen samples, leading to lower ruminal pH (P < 0.05). The WPCSB group showed higher abundance of Bacteroidetes and lower abundance of Firmicutes in the rumen microbiome than the WPCS group (P < 0.05). Multiple differential genera were identified, with Prevotella being the most dominant genus and more abundant in WPCSB samples. Moreover, the enriched functional attributes, including those associated with glycolysis/gluconeogenesis and citrate cycle, were more actively expressed in the WPCSB samples than in the WPCS samples. Additionally, certain glucoside hydrolases that hydrolyse the side chains of hemicelluloses and pectins were also actively expressed in the WPCSB microbiome. These findings suggested that WPCSB increased NDF digestibility in three ways: (1) by increasing the relative abundance of the most abundant genera, (2) by recruiting more functional features involved in glycolysis/gluconeogenesis and citrate cycle pathways, and (3) by increasing the relative abundance and/or expression activity of the glucoside hydrolases involved in hemicellulose and pectin metabolism. Our findings provide novel insights into the microbial mechanisms underlying improvement in the growth performance of sheep/ruminants. However, the biological mechanisms cannot be fully elucidated using only metagenomics tools; therefore, a combined multi-omics approach will be used in subsequent studies.     

Rubber seed oil and flaxseed oil supplementation alter digestion,ruminal fermentation and rumen fatty acid profile of dairy cows

Rubber seed oil (RO) that is rich in polyunsaturated fatty acids (FA) can improve milk production and milk FA profiles of dairy cows; however, the responses of digestion and ruminal fermentation to RO supplementation in vivo are still unknown. This experiment was conducted to investigate the effect of RO and flaxseed oil (FO) supplementation on nutrients digestibility, rumen fermentation parameters and rumen FA profile of dairy cows. Forty-eight mid-lactation Holstein dairy cows were randomly assigned to one of four treatments for 8 weeks, including basal diet (CON) or the basal dietary supplemented with 4% RO, 4% FO or 2% RO plus 2% FO on a DM basis. Compared with CON, dietary oil supplementation improved the total tract apparent digestibility of DM, neutral detergent fibre and ether extracts ( P < 0.05). Oil treatment groups had no effects on ruminal digesta pH value, ammonia N and microbial crude protein ( P > 0.05), whereas oil groups significantly changed the volatile fatty acid (VFA) profile by increasing the proportion of propionate whilst decreasing total VFA concentration, the proportion of acetate and the ratio of acetate to propionate ( P < 0.05). However, there were no differences in VFA proportions between the three oil groups (P > 0.05). In addition, dietary oil supplementation increased the total unsaturated FA proportion in the rumen by enhancing the proportion of trans-11 C18:1 vaccenic acid (VA), cis-9, trans-11 conjugated linoleic acid (CLA) and α-linolenic acid (ALA) ( P < 0.05). These results indicate that dietary supplementation with RO and FO could improve nutrients digestibility, ruminal fermentation and ruminal FA profile by enhancing the VA, cis-9, trans-11 CLA and ALA composition of lactating dairy cows. These findings provide a theoretical basis for the application of RO in livestock production.