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Objective: Objective: This experiment aimed to evaluate the effects of replacing concentrates with cassava root-top silage (CARTOS) on feed intake, digestibility, rumen fermentation, blood parameters, and growth performance of beef cattle. Methods: : Twenty crossbred bulls with a body weight (BW) of 226 ± 56 kg were randomly assigned to one of five treatments for 90 days in a randomized complete block design (RCBD) having four blocks based on BW. The concentrates were replaced by CARTOS at levels of 0, 25, 50, 75, and 100% DM. Animals were fed dietary treatments at 1.8% BW, with rice straw offered ad libitum. Results: : The dry matter (DM) and crude protein (CP) intake were decreased (p<0.01, p=0.04) when the diet's CARTOS level was increased. The digestibility of DM, OM, and CP were not different among treatments, while fiber digestibility was increased with the inclusion of CARTOS (p=0.03). The addition of CARTOS to replace concentrates did not change ruminal pH or volatile fatty acid (VFA) proportions except for acetic acid, which increased with the addition of CARTOS (p=0.03). The ruminal ammonia-nitrogen (NH3-N) was decreased (p<0.01) with increasing levels of CARTOS. The blood glucose and blood urea nitrogen (BUN) decreased (p=0.01) with the addition of CARTOS at 100%, whereas total protein and hematological parameters did not change with increasing levels of CARTOS. The use of CARTOS to substitute concentrates at 75 and 100% decreased average daily gain (ADG) and gain to feed ratio (G:F) (p<0.01); therefore, the addition of CARTOS up to 50% maintained ADG and G:F in beef cattle. Conclusion: : The CARTOS can be replaced for concentrates up to 50% in beef cattle without adversely affecting feed intake, nutrient digestibility, rumen fermentation characteristics, blood parameters, or growth performance of beef cattle.
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BACKGROUND: Rubber seed kernel is a by-product derived from rubber tree plantations. It is rich in C18 unsaturated fatty acids (UFA) and has the potential to be used as a protein source for ruminant diets. This investigation has been conducted to determine the influence of rubber seed kernel pellet (RUSKEP) supplementation on in vitro rumen fermentation characteristics and fatty acid profiles in swamp buffalo. Using a completely randomized design (CRD) and supplementation of RUSKEP at 0, 2, 4, 6, 8, and 10% dry matter (DM) of substrate. RESULTS: The supplementation with RUSKEP had no effect on gas kinetics, cumulative gas production, or degradability. Ruminal pH decreased linearly (P < 0.01) and ammonia-nitrogen (NH3-N) concentration decreased quadratically (P < 0.01) by RUSKEP supplementation. The proportion of acetate (C2) decreased linearly (P < 0.01), but propionate (C3) and butyrate (C4) increased linearly (P < 0.01), resulting in a decrease in the acetate to propionate ratio (C2:C3) (P < 0.01) by RUSKEP supplementation. With an increasing level of dietary RUSKEP, there was a slight increase in UFA in the rumen by increasing the oleic acid (OA; C18:1 cis-9 + trans-9), linoleic acid (LA; C18:2 cis-9,12 + trans-9,12), and α-linolenic acid (ALA; C18:3 cis-9,12,15) concentrations (P < 0.01). CONCLUSIONS: Adding up to 10% of RUSKEP could improve in vitro rumen fermentation and C18 unsaturated fatty acids, especially ALA, in swamp buffalo.
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Alimentación Animal , Búfalos , Ácidos Grasos , Fermentación , Rumen , Semillas , Animales , Rumen/metabolismo , Ácidos Grasos/análisis , Ácidos Grasos/metabolismo , Alimentación Animal/análisis , Semillas/química , Suplementos Dietéticos , Dieta/veterinaria , Hevea/químicaRESUMEN
OBJECTIVE: The aim of this study was to assess the effect of Thai native cattle grazing in the lowland or mountain forest on carcass characteristics, meat quality, sensory palatability, and chemical composition. METHODS: Twelve male Thai native cattle with an average weight of 110±10 kg are allowed to be grazing in the lowland or Phu Phan mountain forest during the rainy season in northeastern Thailand. RESULTS: The carcass characteristics, meat pH, and meat color were unaffected by treatment (p>0.05). The boiling loss was lower in the cattle grazing on the mountain forest (p = 0.027). The cattle grazing in the mountain forest had increased shear force (p = 0.039), tenderness (p = 0.011), and flavor intensity (p = 0.003). The protein and fat were higher (p<0.001 and p = 0.035, respectively) in cattle grazing in the mountain forest. The different grazing systems of the cattle had no effect (p>0.05) fatty acids in meat, except for capric acid (C10:0) and lauric acid (C12:0), which were higher (p = 0.046 and p = 0.049, respectively) when the cattle were grazing in the mountain forest. The different grazing systems did not influence (p>0.05) the unsaturated fatty acids in meat. CONCLUSION: Thai native cattle grazing in the Phu Phan mountain forest in the rainy season improves meat quality, sensory evaluation, and chemical composition.
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This study aimed to compare the effects of adding cyanide-utilizing bacteria (CUB) and sulfur on rumen fermentation, the degradation efficiency of hydrogen cyanide (HCN), feed utilization, and blood metabolites in beef cattle fed two levels of fresh cassava root (CR). A 2 × 2 factorial arrangement in a 4 × 4 Latin square design was used to distribute four male purebred Thai native beef cattle (2.5-3.0 years old) with an initial body weight (BW) of 235 ± 15.0 kg. Factor A was Enterococcus faecium KKU-BF7 oral direct fed at 108 CFU/ml and 3% dry matter (DM) basis of pure sulfur in concentrate diet. Factor B was the two levels of CR containing HCN at 300 and 600 mg/kg on DM basis. There was no interaction effect between CUB and sulfur supplementation with CR on feed utilization (p > 0.05). Similarly, CUB and sulfur supplementation did not affect (p > 0.05) DM intake and apparent nutrient digestibility. However, the high level of CR supplementation increased (p < 0.05) feed intake and neutral detergent fiber digestibility. The ruminal pH, microbial population, ammonia-nitrogen, blood urea nitrogen, and blood thiocyanate concentrations were unaffected by the addition of CUB and sulfur at two CR concentrations (p > 0.05). The addition of CUB or sulfur had no effect on the efficiency of HCN degradation in the rumen (p > 0.05). However, cattle given CR with HCN at 600 mg/kg DM had considerably higher degradation efficiency than those fed CR containing HCN at 300 mg/kg DM (p < 0.05). The group fed CUB had a considerably greater CUB population (p < 0.05) than the sulfur group. Cyanide-utilizing bacteria or sulfur supplementation with CR had no interaction effect between total VFAs and their profiles (p > 0.05). However, the study observed a significant positive correlation between the amount of CR and the concentration of propionate in the rumen (p < 0.05). The levels of nitrogen absorption and nitrogen retention did not differ significantly among the treatments (p > 0.05). Hence, it may be inferred that the administration of a high concentration of CR at a dosage of 600 mg/kg DM HCN could potentially provide advantageous outcomes when animals are subjected to oral CUB incorporation.
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Manihot , Microbiota , Bovinos , Masculino , Animales , Manihot/metabolismo , Cianuros/metabolismo , Digestión , Suplementos Dietéticos/análisis , Dieta/veterinaria , Fermentación , Nitrógeno/metabolismo , Bacterias/metabolismo , Azufre/metabolismo , Rumen/microbiología , Alimentación Animal/análisisRESUMEN
Cyanogenic glycosides in forage species and the possibility of cyanide (CN) poisoning can have undesirable effects on ruminants. The literature estimates that unknown rumen bacteria with rhodanese activity are key factors in the animal detoxification of cyanogenic glycosides, as they are capable of transforming CN into the less toxic thiocyanate. Therefore, identifying these bacteria will enhance our understanding of how to improve animal health with this natural CN detoxification process. In this study, a rhodanese activity screening assay revealed 6 of 44 candidate rumen bacterial strains isolated from domestic buffalo, dairy cattle, and beef cattle, each with a different colony morphology. These strains were identified as belonging to the species Enterococcus faecium and E. gallinarum by 16S ribosomal DNA sequence analysis. A CN-thiocyanate transformation assay showed that the thiocyanate formation capacity of the strains after a 12 h incubation ranged from 4.42 to 25.49 mg hydrogen CN equivalent/L. In addition, thiocyanate degradation resulted in the production of ammonia nitrogen and acetic acid in different strains. This study showed that certain strains of enterococci substantially contribute to CN metabolism in ruminants. Our results may serve as a starting point for research aimed at improving ruminant production systems in relation to CN metabolism.
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Cianuros , Tiosulfato Azufretransferasa , Animales , Bovinos , Cianuros/metabolismo , Tiosulfato Azufretransferasa/metabolismo , Tiocianatos/metabolismo , Enterococcus/metabolismo , Rumen/microbiología , Rumiantes/metabolismoRESUMEN
This study evaluated the effects of cassava pulp fermented with Lactobacillus casei TH14, urea, and molasses on its chemical composition, the fermentation end-product of silage, and aerobic stability. A 2 × 2 × 2 factorial arrangement with a randomized complete block design was employed. The first factor: level of L. casei TH14 [L; 0 and 105 cfu/kg fresh matter (FM)], the second factor: level of molasses (M; 0 and 4% DM), the third factor: level of urea (U; 0 and 4% DM), and the number of days of fermentation (7, 14, and 21 days) were evaluated using a statistical block. There were interactions among CSP fermented with different additives on DM content (p < 0.05). The control group (CON) and CSP fermented with L, L×M, and L×U had lower DM contents than U, U×M, and L×U×M. The crude protein of CSP was increased by interaction of L×U and U×M additives (p < 0.05 and p < 0.01, respectively). Interaction effects between L and U and NDF content were detected (p < 0.05). The L×U combination resulted in a significantly lower NDF than the other groups. The interaction between L×U×M had no effect on the change in the CSP fermentation process (p > 0.05). The combination of U×M caused a poorer pH than other groups (p < 0.01). The ammonia-N content was higher than others, when CSP was fermented with L×U (p < 0.01) or U×M (p < 0.05), respectively. The lactic acid levels in fermented CSP were higher (p < 0.01) than in other groups through the L. casei. The interaction between L×U×M had an influence on lactic acid bacteria (LAB) (p < 0.01) and aerobic bacteria (p < 0.01). The highest LAB population (p < 0.01) at 106 cfu/g FM was found in CSP fermented with L. casei and molasses. In conclusion, the current study shows that CSP treated with L×U×M resulted in good preservation by recovering DM, a low number of aerobic bacteria, and greater LAB than other treatments, with the exception of the L×U×M addition. A 21-day fermentation period is advised because it produces products with greater levels of crude protein, lactic acid, acetic acid, and propionic acid.
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This experiment was conducted to assess the effect of hydrolyzed yeast (HY) on growth performance, nutrient digestibility, rumen fermentation, and hematology in growing crossbred Bos indicus cattle. Twenty crossbred beef cattle with an initial body weight (BW) of 142 ± 12 kg were randomly assigned to one of four treatments for 90 d in a randomized complete block design (RCBD) having five blocks based on a homogenous subpopulation of sex and BW. Cattle were fed with a total mixed ration (TMR) and supplemented with HY at 0, 1, 2, and 3 g/kg dry matter (DM), respectively. Supplementation with the HY did not change average daily gain (ADG), dry matter intake (DMI), and gain to feed ratio (G:F) (p ≥ 0.06). The addition of HY did not adversely affect nutrient intake (p ≥ 0.48), while the digestibility of crude protein (CP) increased quadratically (p= 0.03) in the cattle receiving HY. The addition of HY did not affect rumen pH, but NH3-N concentration increased linearly (p = 0.02) in the cattle. The total volatile fatty acid (total VFA) increased quadratically (p= 0.03) when cattle were fed with HY supplementation. The proportion of acetate decreased cubically (p= 0.03) while propionate increased cubically (p= 0.01), resulting in a decrease in the acetate to propionate ratio (p= 0.01) when cattle were fed with HY supplementation. In addition, acetate was the lowest, but total VFA and propionate were the highest in cattle fed the HY at 2 g/kg DM. Butyrate increased cubically (p = 0.02) with the addition of HY. The protozoal and fungal populations were similar among treatments (p ≥ 0.11), but the bacterial population increased linearly (p < 0.01) with the addition of HY. Supplementation of HY did not influence blood urea nitrogen (BUN), red blood cells (RBC), hemoglobin, hematocrit, white blood cells (WBC), lymphocytes, or eosinophils (p≥ 0.10). However, monocytes and neutrophils increased linearly (p = 0.04 and p = 0.01, respectively) by HY supplementation. In conclusion, supplementation of HY at 2 g/kg DM promotes CP digestibility, rumen fermentation efficiency, and hematology but does not affect the growth performance of growing beef cattle.
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This experiment was conducted to assess the effect of indigo waste on the feed intake, digestibility, rumen fermentation, hematology, immune response and growth performance in growing beef cattle. Twenty crossbred beef cattle with an initial body weight (BW) of 145 ± 11 kg were fed four levels of indigo waste for 90 days in a trial. Additions of indigo waste at 0%, 10%, 20% and 30% in a concentrate diet using a completely randomized design (CRD). Cattle were fed concentrate at 1.8% BW, with rice straw fed ad libitum. The concentrate intake decreased linearly (p = 0.01) with the addition of indigo waste. The supplementation with indigo waste reduced dry matter (DM) and organic matter (OM) digestibility cubically (p = 0.03 and p = 0.02, respectively), while increasing neutral detergent fiber (NDF) digestibility cubically (p = 0.02). The final BW of beef cattle decreased linearly (p = 0.03) with the addition of indigo waste. The inclusion of indigo waste decreased the average daily gain (ADG) and gain-to-feed ratio (G:F) linearly (p < 0.01) from 0 to 90 days. The nutrient digestibility, ADG and G:F of beef cattle fed 10% indigo waste in the diet was similar when compared with the control (0% indigo waste). The ruminal pH, ammonia-nitrogen (NH3-N) and total volatile fatty acid (VFA) concentrations were similar among treatments (p > 0.05). The proportion of acetate increased linearly (p < 0.01) but propionate decreased linearly (p < 0.01), resulting in an increase in the acetate to propionate ratio (p < 0.01) when cattle were fed with indigo waste supplementation. Increasing indigo waste levels did not influence blood urea nitrogen (BUN) levels, hematological parameters or immune responses (IgA, IgM and IgG) (p > 0.05). In conclusion, the inclusion of indigo waste at 10% in a concentrate diet did not have a negative effect on feed intake, nutrient digestibility, rumen fermentation, hematology, immune function or growth performance in growing beef cattle.
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Improving the nutrition of livestock is an important aspect of global food production sustainability. This study verified whether lactic acid bacteria (LAB) inoculant could promote ensiling characteristics, nutritive value, and in vitro enteric methane (CH4) mitigation of forage sorghum (FS) mixture silage in attacking malnutrition in Zebu beef cattle. The FS at the soft dough stage, Cavalcade hay (CH), and cassava chip (CC) were obtained. The treatments were designed as a 4 × 2 factorial arrangement in a completely randomized design. Factor A was FS prepared without or with CH, CC, and CH + CC. Factor B was untreated or treated with Lactobacillus casei TH14. The results showed that all FS mixture silages preserved well with lower pH values below 4.0 and higher lactic acid contents above 56.4 g/kg dry matter (DM). Adding LAB boosted the lactic acid content of silages. After 24 h and 48 h of in vitro rumen incubation, the CC-treated silage increased in vitro DM digestibility (IVDMD) with increased total gas production and CH4 production. The LAB-treated silage increased IVDMD but decreased CH4 production. Thus, the addition of L. casei TH14 inoculant could improve lactic acid fermentation, in vitro digestibility, and CH4 mitigation in the FS mixture silages.
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Lacticaseibacillus casei/metabolismo , Metano/biosíntesis , Ensilaje/microbiología , Recuento de Colonia Microbiana , Fermentación , Técnicas In Vitro , Lacticaseibacillus casei/aislamiento & purificación , SorghumRESUMEN
This study's objectives were to (a) consider the combined effects of Lactobacillus casei TH14 and additives on fermentation quality, nutritive value and microbial composition when ensiling rice straw and (b) evaluate the ensiled rice straw using the in vitro gas production technique. A 2 × 2 × 2 factorial arrangement in a completely randomized design (CRD) was used in a randomized complete design with three replications. The rice straw was treated with L. casei TH14 (T) at 0 and 105 colony-forming unit (cfu)/kg fresh matter (FM), cellulase (C) at 0 and 10,000 unit/kg FM and molasses (M) at 0 and 50 g/kg FM. After 30 days, the dry matter content of the ensiled rice straw was a range between 261.77 and 287.01 g/kg while untreated rice straw was 934.00 g/kg. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents were decreased when treated with C (p < .01). Th e pH, ammonia-nitrogen, lactic acid, acetic acid and butyric acid values were affected by the interaction among the additives. In particular, pH was significantly (p < .01) lower in rice straw treated with T × C × M. Lactic acid bacterium (LAB) counts were highest when ensilage rice straw with T × C × M (p < .05), while untreated rice straw indicated highest amount for aerobic bacteria (p < .01) and yeast populations (p < .01). Interaction among additives had no effect (p > .05) on gas production rate constant for the insoluble fraction (c value), but combination between C × M with ensiled rice straw reduced the c value (p < .05). The in vitro dry matter digestibility at 48 hr after incubation increased when rice straw was treated with T × C (p < .01), T × M (p < .05) and C × M (p < .05). Total volatile fatty acids at 4 hr and the mean value were increased (p < .05) when ensiled rice straw with T × C or T × M. Propionic acid was improved by adding C or M (p < .05). T × M did not influence (p > .05) any ruminal microorganism counts except for bacterial counts at 4 hr (p < .01). Thus, ensiled rice straw with T × C × M could promote the quality of ensiled rice straw and improve gas kinetics, fibre digestion and ruminal characteristics.
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Lacticaseibacillus casei , Oryza , Animales , Fermentación , Cinética , Distribución Aleatoria , Ensilaje/análisisRESUMEN
OBJECTIVE: To find out ways of improving fermentation quality of silage, the comparative analysis of fermentation characteristics and in vitro digestibility of tropical grasses silage applied with cellulases produced from Acremonium or Tricoderma species were studied in Thailand. METHODS: Fresh and wilted Guinea grass and Napier grass silages were prepared with cellulases from Acremonium (AC) or Trichoderma (TC) at 0.0025%, 0.005%, and 0.01% on a fresh matter (FM), and their fermentation quality, chemical composition and in vitro digestibility were analyzed. RESULTS: All silages of fresh Napier grass were good quality with lower pH, butyric acid, and ammonia nitrogen, but higher lactic acid content than wilted Napier grass and Guinea grass silage. Silages treated with AC 0.01% had the best result in terms of fermentation quality. They also had higher in vitro dry matter digestibility and in vitro organic matter digestibility at 6 and 48 h after incubation than other silages. Silages treated with lower levels at 0.005% or 0.0025% of AC and all levels of TC did not improve silage fermentation. CONCLUSION: The AC could improve silage fermentation and in vitro degradation of Guinea grass and Napier grass silages, and the suitable addition ration is 0.01% (73.5 U) of FM for tropical silage preparation.
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OBJECTIVE: The effects of lactic acid bacteria (LAB) and cellulase enzyme on fermentation quality, microorganism population, chemical composition and in vitro gas production of sorghum silages were studied. METHODS: Commercial inoculant Lactobacillus plantarum Chikuso 1 (CH), local selected strain Lactobacillus casei (L. casei) TH 14 and Acremonium cellulase (AC) were used as additives in sorghum silage preparation. RESULTS: Prior to ensiling Sorghum contained 104 LAB and 106 cfu/g fresh matter coliform bacteria. The chemical compositions of sorghum was 26.6% dry matter (DM), 5.2% crude protein (CP), and 69.7% DM for neutral detergent fiber. At 30 days of fermentation after ensiling, the LAB counts increased to a dominant population; the coliform bacteria and molds decreased to below detectable level. All sorghum silages were good quality with a low pH (<3.5) and high lactic acid content (>66.9 g/kg DM). When silage was inoculated with TH14, the pH value was significantly (p<0.05) lower and the CP content significantly (p<0.05) higher compared to control, CH and AC-treatments. The ratio of in vitro methane production to total gas production and DM in TH 14 and TH 14+AC treatments were significantly (p<0.05) reduced compared with other treatments while in vitro dry matter digestibility and gas production did not differ among treatments. CONCLUSION: The results confirmed that L. casei TH14 could improve sorghum silage fermentation, inhibit protein degradation and decrease methane production.
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Natural lactic acid bacteria (LAB) populations in tropical grasses and their fermentation characteristics on silage prepared with cellulase enzyme and LAB inoculants were studied. A commercial inoculant Lactobacillus plantarum Chikuso 1 (CH), a local selected strain Lactobacillus casei TH14 (TH14), and 2 cellulases, Acremonium cellulase (AC) and Maicelase (MC; Meiji Seika Pharma Co. Ltd., Tokyo, Japan), were used as additives to silage preparation with fresh and wilted (6 h) Guinea grass and Napier grass. Silage was prepared using a laboratory-scale fermentation system. Treatments were CH, TH14, AC at 0.01% fresh matter, AC 0.1%, MC 0.01%, MC 0.1%, CH+AC 0.01%, CH+AC 0.1%, CH+MC 0.01%, CH+MC 0.1%, TH14+AC 0.1%, TH14+AC 0.01%, TH14+MC 0.1%, and TH14+MC 0.01%. Microorganism counts of Guinea grass and Napier grass before ensiling were 102 LAB and 106 aerobic bacteria; these increased during wilting. Based on morphological and biochemical characteristics, and 16S rRNA gene sequence analysis, natural strains from both grasses were identified as L. plantarum, L. casei, Lactobacillus acidipiscis, Leuconostoc pseudomesenteroides, Leuconostoc garlicum, Weissella confusa, and Lactococcus lactis. Lactobacillus plantarum and L. casei are the dominant species and could grow at lower pH and produce more lactic acid than the other isolates. Crude protein and neutral detergent fiber were 5.8 and 83.7% of dry matter (DM) for Guinea grass, and 7.5 and 77.1% of DM for Napier grass. Guinea grass had a low level of water-soluble carbohydrates (0.39% of DM). Guinea grass silage treated with cellulase had a lower pH and higher lactic acid content than control and LAB treatments. The 0.1% AC and MC treatments had the best result for fermentation quality. All high water-soluble carbohydrate (2.38% DM) Napier grass silages showed good fermentation quality. Compared with control and LAB-inoculated silage, the cellulase-treated silages had significantly higher crude protein content and lower neutral detergent fiber and acid detergent fiber contents. The results confirmed that cellulase could improve tropical silage quality, inhibiting protein degradation and promoting fiber degradation.
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Fermentación , Ensilaje , Animales , Celulasa/metabolismo , Análisis Factorial , Ácido Láctico , Lactobacillus/metabolismo , ARN Ribosómico 16S/genéticaRESUMEN
Strains TH 14, TH 21 and TH 64 were isolated from tropical silages, namely corn stover, sugar cane top and rice straw, respectively, prepared in Thailand. These strains were selected by low pH growth range and high lactic acid-producing ability, similar to some commercial inoculants. Based on the analysis of 16S ribosomal RNA gene sequence and DNA-DNA relatedness, strain TH 14 was identified as Lactobacillus casei, and strains TH 21 and TH 64 were identified as L. plantarum. Strains TH 14, TH 21, TH 64 and two commercial inoculants, CH (L. plantarum) and SN (L. rhamnosus), were used as additives to fresh and wilted purple Guinea and sorghum silages prepared using a small-scale fermentation method. The number of epiphytic lactic acid bacteria (LAB) in the forages before ensilage was relatively low but the numbers of coliform and aerobic bacteria were higher. Sorghum silages at 30 days of fermentation were all well preserved with low pH (3.56) and high lactic acid production (72.86 g/kg dry matter). Purple Guinea silage inoculated with LAB exhibited reduced count levels of aerobic and coliform bacteria, lower pH, butyric acid and ammonia nitrogen and increased lactic acid concentration, compared with the control. Strain TH 14 more effectively improved lactic acid production compared with inoculants and other strains. © 2016 Japanese Society of Animal Science.
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Lactobacillus , Ensilaje/microbiología , Fermentación , Concentración de Iones de Hidrógeno , Ácido Láctico/biosíntesis , Lactobacillus/aislamiento & purificación , Lactobacillus/metabolismo , Poaceae , Sorghum , Tailandia , Clima TropicalRESUMEN
Four Thai male native beef cattle, initial body weight (BW) of 100 ± 3.0 kg were randomly assigned in a 4 × 4 Latin square design to receive four dietary treatments with inclusion of urea calcium sulphate mixture (U-cas) in feed block (FB) at 0, 120, 150, and 180 g/kg dry matter (DM). Total intakes were increased with the increasing level of U-cas supplementation in FB and the result obtained the highest when supplementation of U-cas in FB at 180, followed by 150, 120, and 0 g/kg DM, respectively. Moreover, supplementation of U-cas in FB at 180 g/kg DM could reduce total N excretion (4.1 g/day), as compared to others treatments, while N retention and proportion of N retention to N intake were increased up to 6.9 g/day and 14.9 %, respectively. On the other hand, the blood biochemistry and hematological parameters were not different among treatments except concentration of plasma urea N, plasma glucose, and total blood protein were improved especially with U-cas supplementation at 180 g/kg DM in FB. In conclusion, supplementation of U-cas at 180 g/kg in FB improved feed intake, N utilization, and blood biochemistry in Thai native beef cattle fed on rice straw.