Prediction of enteric methane production from dairy cows

Abstract

The main objective of this study was to elucidate the potential for prediction of enteric methane (CH₄) emissions from dairy cows by using predicted rumen plus hindgut digested (fermented nutrients) and total tract digested nutrients (by using NorFor) as input variables. Twenty-one experiments (78 dietary treatments) were collected. The data-set was used to develop prediction models and to test their and extant models ability to predict enteric CH₄ emissions. Models were compared based on mean squared prediction error and concordance correlation coefficient (CCC) analysis. Fermented nutrients did not predict enteric CH₄ emissions adequately (CCC < 0.420). Including total digested (td) nutrients in the model [CH₄ (MJ/d) = ?2.13 + 1.64 tdOM (kg/d) ?9.74 tdFat (kg/d) + 1.64 tdNDF (kg/d)] predicted enteric CH₄ emissions more precisely (CCC = 0.733), and showed an improvement in the prediction of enteric CH₄ emissions over the extant models tested.     

Prediction of enteric methane emission from beef cattle in Southeast Asia

We conducted a meta‐data analysis to develop prediction equations to estimate enteric methane (CH₄) emission from beef cattle in Southeast Asia. The dataset was obtained from 25 studies, which included 332 individual observations on nutrient intakes, digestibilities, and CH₄ emissions. Cattle were provided tropical forage or rice straw, with or without concentrates in individual pens equipped with indirect open‐circuit head hood apparatus. The simplest and best equation to predict daily CH₄ emission was CH₄ (g/day) = 22.71 (±1.008) × dry matter intake (DMI, kg/day) + 8.91 (±10.896) [R² = 0.77; root mean square error (RMSE) = 19.363 g/day]. The best equation to predict CH₄ energy as a proportion of gross energy intake (CH₄‐E/GEI, J/100 J) was obtained using DMI per body weight (DMIBW, kg/100 kg), content (g/100 g DM) of ether extract (EE) and crude protein (CP), and DM digestibility (DMD, g/100 g); CH₄‐E/GEI = ?0.782 (±0.2526) DMIBW ? 0.436 (±0.0548) EE ? 0.073 (±0.0218) CP + 0.049 (±0.0097) DMD + 8.654 (±0.6517) (R² = 0.39; RMSE = 1.3479 J/100 J GEI). It was indicated that CH₄ emissions from beef cattle in Southeast Asia are predictable using present developed models including simple indices.     

Free ferulic acid uptake in ram lambs

The objective of this research was to investigate the fate of free ferulic acid (FA) in sheep. Ferulic acid is normally present in plants, bound to the indigestible cell wall. If the FA present in a ruminant diet is released from the cell wall with feed pretreatment methods, FA may be released into the rumen for digestion or absorption into the bloodstream or both. Eight male Dorset × Finn lambs were randomly assigned to 1 of 4 treatment (trt) concentrations, 0 (control), 3, 6, or 9 g/d free FA as part of a replicated 4 × 4 Latin square design. Lambs were housed individually and consumed chopped alfalfa hay (Medicago sativa; 22.8% CP, 39.3% NDF, 0.73 Mcal/kg NE(g)) ad libitum and 350 g corn grain (Zea mays L.; 9.1% CP, 11.2% NDF, 1.52 Mcal/kg NE(g)) once daily at 0800 h. Basal concentrations of FA in hay, grain, blood, feces, and urine were established following a 14-d adjustment to diet and housing. An oral dose of free FA was administered for 5 d via bolus after each morning feeding, after which hay, grain, blood, feces, and urine were sampled. Body weights were recorded at the beginning and end of each trt, and DMI was measured daily during trt periods. In addition to trt, each lamb ingested a daily average of 3.78 g FA in its bound form via the offered hay (2.67 mg/g FA; 1.0 kg/d DMI) and corn (3.17 mg/g FA; 0.35 kg/d DMI). The FA administered had a quadratic effect on average hay DMI (1.25, 1.41, 1.41, and 1.29 kg/d for 0, 3, 6, or 9 g/d FA trt; P < 0.01; SE = 58.9 g), but lamb BW did not change as a result of FA trt (P = 0.28). The NDF content and amount of FA in refusals were not affected by trt, (P = 0.30; P = 0.82, respectively). Fecal FA did not differ among trt or when compared with basal FA (P = 0.53), while urine FA increased as FA dose increased (P < 0.01), indicating that free FA was absorbed and transferred into urine. No free FA was found in the plasma analyzed, suggesting that disappearance from the blood of absorbed free FA occurred within the 5 h that passed between bolus dosage and blood collection. An in vitro analysis was conducted to assess the degree of inhibition of microbial NDF digestion caused by FA supplementation. In vitro, NDF disappearance was not inhibited as a result of FA treatment (P = 0.80). These data in combination with the results of the lamb study indicate that free FA as 0.24, 0.43, and 0.70% of DMI in lambs is absorbed and excreted in the urine as opposed to the feces with no apparent effects on rumen microbial NDF digestion.     

Development of prediction equation for methane‐related traits in beef cattle under high concentrate diets

The objective of this study was to develop a prediction equation for methane‐related traits in beef cattle and evaluate this equation using datasets with different cattle breeds and roughage rates. Enteric methane emission (CH₄, l/day) was measured using open‐circuit respiration chambers. Dry matter intake (DMI, kg/day), body weight (BW, kg), daily gain (DG, kg), total digestible nutrients (TDN, %DMI), and roughage rate (Rrate, %) were used as independent variables, and methane‐related traits—CH₄, CH₄ per DMI (CH₄/DMI, l/kg), and methane conversion factor (MCF, %)—were used as dependent variables. The best‐fit equations to predict methane‐related traits using a total of 76 records were CH₄ = –676.7 + 0.04194 × BW + 29.88 × DMI + 7.883 × TDN + 4.367 × Rrate, CH₄/DMI = –52.24 – 1.193 × 10^–3 × BW – 5.905 × DG + 1.077 × TDN + 0.5008 × Rrate, and MCF = –11.43 – 5.308 × 10^–4 × BW – 1.223 × DG + 0.2336 × TDN + 0.1157 × Rrate. The predictive ability of the developed equations differed between roughage rates but not between breeds. For CH₄, the predictive ability of the developed equations was better compared with previously reported equations in the low roughage rate dataset, but not in the high roughage rate dataset. Our results suggest that the developed equations of methane‐related traits can be applied in beef cattle fed with low roughage diets.     

Prediction of enteric methane emissions from lactating cows using methane to carbon dioxide ratio in the breath

The aim of this study was to develop prediction equations for methane (CH₄) emissions from lactating cows using the CH₄/carbon dioxide (CO₂) ratio in the breath measured in the automatic milking system (AMS) and to evaluate the predicted values and factors affecting the CH₄/CO₂ ratio. The model development was conducted using a dataset determined in respiration chambers or head boxes (n = 121). Then, gas measurements in the AMS as well as in the head box were carried out with six lactating cows fed one of three different levels of neutral detergent fiber (NDF) content, following a 3 × 3 Latin square experimental design. The obtained equation that is suitable for practical use on farms to predict CH₄ was CH₄ (L/day) = −507 + 0.536 live weight (kg) + 8.76 energy-corrected milk (kg/day) + 5,029 CH₄/CO₂ (adjusted R² = 0.83; root mean square error = 40.8 L/day). Results showed that the predicted values correlated positively with the observed values, the determined CH₄/CO₂ ratio increased with increasing dietary NDF content, and the detected eructation rate was in the normal range. On the other hand, the CH₄/CO₂ ratio was affected by the time interval between measurement and last eating before the measurement.     

Energy utilization,nitrogen balance and microbial protein supply in cattle fed Pennisetum purpureum and condensed tannins

The aim of the experiment was to assess the effect of condensed tannins (CT) on feed intake, dry matter digestibility, nitrogen balance, supply of microbial protein to the small intestine and energy utilization in cattle fed a basal ration of Pennisetum purpureum grass. Five heifers (Bos taurus × Bos indicus) with an average live weight of 295 ± 19 kg were allotted to five treatments consisting of increasing levels of CT (0, 1, 2, 3 and 4% CT/kg DM) in a 5 × 5 Latin square design. Dry matter intake (DMI) was similar (p > 0.05) between treatments containing 0, 1, 2 and 3% of CT/kg DM and it was reduced (p < 0.05) to 4% CT (5.71 kg DM/day) with respect to that observed with 0% CT (6.65 kg DM/day). Nitrogen balance, purine derivatives excretion in urine, microbial protein synthesis and efficiency of synthesis of microbial nitrogen in the rumen were not affected (p ≥ 0.05) by the increase in the levels of condensed tannins in the ration. Energy loss as CH₄ was on average 2.7% of the gross energy consumed daily. Metabolizable energy intake was 49.06 MJ/day in cattle fed low‐quality tropical grass with a DMI of 6.27 kg/day. It is concluded that concentrations of CT between 2 and 3% of DM of ration reduced energy loss as CH₄ by 31.3% and 47.6%, respectively, without affecting intakes of dry and organic matter; however, digestibilities of dry and organic matter are negatively affected.     

Dietary supplementation with mulberry leaf flavonoids inhibits methanogenesis in sheep

The effects of flavonoids on methanogenesis and microbial flora in Dorper × thin‐tailed Han crossbred ewes were evaluated in two experiments. To investigate the effects of flavonoids on nutrient digestibility and nitrogen balance, 18 ewes (60.0 ± 1.73 kg body weight (BW)) were allotted to two dietary treatments in experiment one, a control diet and the control diet supplemented with flavonoids (2 g/head/day). In experiment two, the effects of supplementary flavonoids on ruminal fermentation and microbial flora were investigated using quantitative polymerase chain reaction with six ewes (67.2 ± 0.79 kg BW) with ruminal cannula assigned to the identical dietary treatments used in experiment one. Supplementary flavonoids improved the apparent digestibility of nitrogen (N, P < 0.001) and neutral detergent fibre (NDF, P = 0.024) and decreased daily CH₄ output (P < 0.001). The ruminal pH (P = 0.638) and ammonia (P = 0.690) were not affected by supplementary flavonoids, whereas the total volatile fatty acid (VFA) content increased (P = 0.037). Supplementary flavonoids decreased ruminal populations of protozoans (P = 0.002) and methanogens (P < 0.001) and increased the populations of Fibrobacter succinogenes (P = 0.016). In conclusion, flavonoids improved the digestibility of organic matter and reduced CH₄ output by inhibiting the populations of microbes involved in methanogenesis.     

玉米干酒糟及其可溶物有效能值估测模型中定标样品选择方法的研究

本试验旨在探讨玉米干酒糟及其可溶物(DDGS)有效能值估测模型中定标样品的选择原则。从23个玉米DDGS样品(定义为全样品库)中按酶水解物能值(EHGE)相差0.21 MJ/kg左右的梯度选择9个定标玉米DDGS样品,定义为选择性样品库;将剩余的14个玉米DDGS样品定义为非选择性样品库。然后,比较选择性样品库与非选择性样品库化学成分含量及变异的差异,以及通过全样品库和选择性样品库分别建立其化学成分对EHGE之间的回归模型,比较根据回归模型计算得到的非选择性样品库EHGE的差异。结果表明,选择性样品库和非选择性样品库的玉米DDGS在粗蛋白质(CP)、粗灰分(Ash)、粗脂肪(EE)、粗纤维(CF)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)含量及EHGE平均值上均无显著性差异(P0.05),CP、Ash、EE、CF、ADF、NDF含量及EHGE变异的方差上均无显著性差异(P0.05)。选择性样品库和非选择性样品库化学成分含量在第一、二主成分得分载荷分布上,选择性样品库中仅1个玉米DDGS样品未与非选择性样品库的分布范围重叠。以选择性样品库样品建立的EHGE预测模型为EHGE=(3 566+53.94×EE-32.68×NDF)×4.184/1 000(R2=0.798 1,RSD=0.43 MJ/kg);以全样品库样品建立的预测模型为EHGE=(3 742+29.67×EE-29.71×NDF)×4.184/1 000(R2=0.535 0,RSD=0.44 MJ/kg)。由2个模型获得的非选择性样品库(n=14)玉米DDGS的EHGE计算值与其实测值的绝对残差平均值分别为0.47和0.33 MJ/kg,差异不显著(P0.05)。综上所述,在玉米DDGS有效能值的估测建模中,以EHGE作为定标样品的选择依据是可行的。     

日粮不同NDF/NFC水平对周岁后荷斯坦奶牛生产性能、营养物质消化率、瘤胃发酵特征和甲烷排放的影响

本试验研究了日粮中不同中性洗涤纤维/非纤维性碳水化合物（NDF/NFC）水平对周岁后荷斯坦奶牛生产性能、营养物质消化率、瘤胃发酵特征及甲烷产量的影响，并在此基础上建立了甲烷排放预测模型，旨在获得我国生产模型下的甲烷排放规律和甲烷转化因子，为提高奶牛能量利用效率、建立国家或区域性温室气体排放清单和探索减排策略提供科学依据和支撑。将45头体况良好，平均为15月龄的荷斯坦后备奶牛随机分为3组，每组15头牛：低日粮NDF/NFC组（NDF/NFC=0.60）、中日粮NDF/NFC组（NDF/NFC=0.75）和高日粮NDF/NFC组（NDF/NFC=0.90），试验期为70 d，包括14 d的预饲期和56 d的正试期。结果表明：1）提高日粮NDF/NFC水平显著降低了奶牛的干物质采食量、有机物采食量、平均日增重、干物质和粗蛋白的表观消化率（P<0.05）；2）提高日粮NDF/NFC水平显著增加了瘤胃内总挥发性脂肪酸产量、乙酸的相对含量和乙酸/丙酸比例（P<0.05），显著降低了丙酸的相对含量（P<0.05）；3）随着日粮NDF/NFC水平的提高，瘤胃甲烷和甲烷能产量、甲烷/代谢体重、甲烷/干物质采食量、甲烷/有机物采食量、甲烷/中性洗涤纤维采食量显著提高（P<0.05）。甲烷转化因子也随着日粮NDF/NFC水平的增加而显著提高（P<0.05）；4）基于体重、采食量、营养物质含量和NDF/NFC分别建立了甲烷预测模型，其中基于干物质采食量和中性洗涤纤维采食量建立的预测模型的决定系数最高（R²=0.77）。因此，提高日粮中NDF/NFC水平可显著降低周岁后荷斯坦奶牛的生产性能、营养物质消化率和瘤胃内丙酸的相对含量，可显著提高瘤胃甲烷产量和甲烷转化因子。     

The effect of very low food intake on digestive physiology and forage digestibility in horses

Equid digestion is often conceptualized as a high‐throughput/low‐efficiency system, in particular compared with ruminants. It is commonly assumed that ruminants have an advantage when resources are limited; the effect of low food intake on digestive physiology of horses has, however, not been explored to our knowledge. We used four adult ponies [initial body mass (BM) 288 ± 65 kg] in two subsequent trials with grass hay‐only diets [in dry matter (DM): hay1, mid‐early cut, crude protein (CP) 10.5%, neutral detergent fibre (NDF) 67.6%; hay2, late cut, CP 5.8%, NDF 69.5%], each fed subsequently at four different dry matter intake (DMI) levels: ad libitum and at 75, 55 and 30 g/kg^0.75/day. We particularly expected digesta mean retention times (MRT) to increase, and hence fibre digestibility to increase, with decreasing DMI. Ponies maintained BM on the first, but lost BM and body condition on DMI55 and DMI30. MRTs were negatively correlated to DMI and ranged (for particles <2 mm) from 23/31 h (hay1/2) on the ad libitum to 38/48 h on DMI30. Digestibilities of DM, nutrients and fibre components decreased from DMI75 to DMI30; apparent digestibilities of organic matter and NDF (hay1/2) dropped from 47/43% and 42/37%, respectively, on the ad libitum DMI to 35/35% and 30/28% on DMI30. Additional differences evident between the two hays included a higher estimated ‘true’ protein digestibility for hay1 and finer faecal particles on hay2; there were no differences in faecal particle size between intake levels. The results suggest that below a certain food intake threshold, the major digestive constraint is not fermentation time but nutrient supply to gut bacteria. The threshold for such an effect probably varies between feeds and might differ between ruminants and equids.     

Effects of supplementing rare earth element cerium on rumen fermentation,nutrient digestibility,nitrogen balance and plasma biochemical parameters in beef cattle

The objectives of the trial were to investigate the effects of supplementing rare earth element (REE) cerium (Ce) on rumen fermentation, nutrient digestibility, methane (CH₄) production, nitrogen (N) balance and plasma biochemical parameters in beef cattle. Four Simmental male cattle, aged at 14 months, with initial liveweight of 355 ± 8 kg and fitted with permanent rumen cannulas, were used as experimental animals. The cattle were fed with a total mixed ration (TMR) composed of concentrate mixture and corn silage. Four levels of cerium chloride (CeCl₃·7H₂O, purity 99.9%), that is 0, 80, 160 and 240 mg CeCl₃/kg DM, were added to basal ration in a 4 × 4 Latin square design. Each experimental period lasted 15 days, of which the first 12 days were for pre‐treatment and the last 3 days were for sampling. The results showed that supplementing CeCl₃ at 160 or 240 mg/kg DM increased neutral detergent fibre (NDF) digestibility (p < 0.05) and tended to increased acid detergent fibre (ADF) digestibility (p = 0.083). Supplementing CeCl₃ at 80, 160 or 240 mg/kg DM decreased the molar ratio of rumen acetate to propionate linearly (p < 0.05). Supplementing CeCl₃ at 160 or 240 mg/kg DM decreased total N excretion, urinary N excretion and increased N retention (p < 0.05), increased excretion of total urinary purine derivatives (PD) (p < 0.05) and decreased CH₄/kg DMI (p < 0.05). In conclusion, supplementing CeCl₃ at 160 or 240 mg/kg DM in the ration of beef cattle increased the digestibility of NDF, decreased the molar ratio of rumen acetate to propionate, increased N retention and microbial N flow and decreased CH₄/kg DMI.     

Methane emission of Santa Inês sheep fed cottonseed by-products containing different levels of gossypol

The aim of this study was to evaluate the methane (CH₄) emission of Santa Inês sheep fed cottonseed by-products, verifying if the gossypol content of these feedstuffs affects CH₄ emission. Twelve late-lactating Santa Inês sheep (44.8?±?7.5 kg body weight (BW)) were allocated in metabolic cages for an experimental period of 19 days, 14 days for adaptation and 5 days for measuring CH₄ emission and dry matter intake (DMI). The animals were divided into four treatments, established in accordance with the cottonseed by-product used in concentrate formulation: Control (CON - no cottonseed by-product), Whole cottonseed (WCS), Cottonseed cake (CSC), and Cottonseed meal (CSM). The free gossypol level of the concentrates were 0, 1,276, 350, and 190 ppm for CON, WCS, CSC, and CSM, respectively. Also, the animals received Cynodon dactylon cv. Coast Cross hay, water, and mineral salt ad libitum. The ether extract content of the diets was balanced between treatments by including soybean oil in concentrates. The technique used to measure the CH₄ emission was the sulfur hexafluoride (SF₆) tracer technique, and the gas samples collected were quantified by analysis in gas chromatography system. The CH₄ emission was evaluated considering the daily emission (g CH₄/day); DMI (g CH₄/kg DMI); and BW (g CH₄/kg BW). No statistical difference was found (P?>?0.05) between treatments for DMI and CH₄ parameters. In the regression analysis, no significant relation (P?>?0.05) between gossypol content and CH₄ emission was observed. These results suggest that gossypol does not affect rumen methanogenesis.     

Rough Agave Flowers as a Potential Feed Resource for Growing Goats

The objective of this study was to evaluate the effect of different levels of rough agave (Agave scabra Ortega) flowers on dry matter intake (DMI), average daily gain (ADG), volatile fatty acid (VFA) production in the rumen, and particular serum metabolites and minerals of native × dairy growing goats (Capra hircus L.). Forty female goats with an initial weight of 11.1 ±  kg (mean ± SD) were used in a completely randomized design experiment that lasted for 84 d. Goats were fed a completely mixed ration (30% roughage, 70% ground corn [Zea mays L.] and soybean [Glycine max {L.} Merr] meal). Treatments consisted of offering goats (4 pens · group⁻¹, 2 goats · pen⁻¹) air-dry rough agave flowers, which replaced alfalfa (Medicago sativa L.) hay at 0% (control; T0), 25% (T25), 50% (T50), 75% (T75), and 100% (T100) of the of the roughage portion of the diet. Values of nutritional parameters for rough agave flowers were in vitro organic matter digestibility, 493 g · kg⁻¹; crude protein, 115 g · kg⁻¹; and metabolizable energy, 6.29 MJ · kg⁻¹ DMI. There were differences (P < 0.05) in ADG (range, 108–155 g · d⁻¹) between diets. Goats fed T0 had higher (P < 0.05) gains than goats fed T50 and T100. DMI was not affected by dietary treatments (range, 3.4% to 3.6% of body weight). Feed conversion ratio (FCR, defined as DMI/ADG) increased (P < 0.05) 27% with total substitution of alfalfa by rough agave flowers, in comparison with T0. Lower (P < 0.05) values of total VFA were obtained with T100, in comparison with all other dietary treatments. These results demonstrated that totally replacing alfalfa with rough agave flowers in diets did not affect DMI but decreased AGD and compromised FCR. Thus, rough agave flowers have the potential to partially replace alfalfa in diets for growing goats.     

Tropical tanniniferous legumes used as an option to mitigate sheep enteric methane emission

This study presents the first results from Brazil using SF₆ tracer technique adapted from cattle to evaluate the capability of condensed tannin (CT) present in three tropical legume forages, Leucaena leucocephala (LEU), Styzolobium aterrimum (STA), and Mimosa caesalpiniaefolia Benth (MIM) to reduce enteric CH₄ production in Santa Inês sheep. Twelve male lambs [27.88?±?2.85 kg body weight (BW)] were allocated in individual metabolic cages for 20-day adaptation followed by 6 days for measuring dry matter intake (DMI) and CH₄ emission. All lambs received water, mineral supplement, and Cynodon dactylon v. coast-cross hay ad libitum. The treatments consisted of soybean meal (710 g/kg) and ground corn (290 g/kg) [control (CON)]; soybean meal (150 g/kg), ground corn (30 g/kg), and Leucaena hay (820 g/kg) (LEU); soybean meal (160 g/kg), ground corn (150 g/kg), and Mucuna hay (690 g/kg) (STA); and soybean meal (280 g/kg), ground corn (190 g/kg), and Mimosa hay (530 g/kg) (MIM); all calculated to provide 40 g/kg CT (except for CON). DMI (in grams of DMI per kilogram BW per day) was lower for LEU (22.0) than CON (29.3), STA (31.2), and MIM (31.6). The LEU group showed emission of 7.8 g CH₄/day, significantly lower than CON (10.5 g CH₄/day), STA (10.4 g CH₄/day), and MIM (11.3 g CH₄/day). However, when the CH₄ emission per DMI was considered, there were no significant differences among treatments (0.37, 0.36, 0.33, and 0.35 g CH₄/g DMI/kg BW/day, respectively, for CON, LEU, STA, and MIM). The sheep receiving STA had shown a tendency (p?=?0.15) to reduce methane emission when compared to the CON group. Therefore, it is suggested that tropical tanniniferous legumes may have potential to reduce CH₄ emission in sheep, but more research is warranted to confirm these results.     

波尔山羊×隆林杂交羔羊育肥期能量和蛋白质营养需要的研究

试验旨在研究育肥期波本杂肉羊能量和蛋白质营养需要量参数,筛选出一个最佳能量和蛋白质搭配的饲料配方,为科学饲养提供理论依据和生产指导。试验选择16只3月龄断奶波隆杂交F1代公羔,采用4×4拉丁方设计,以NRC（1981）营养需要推荐量为参考设计了低能低氮、高能低氮、低能高氮和高能高氮（NRC）4种能氮比日粮,分别为日粮1、2、3和日粮4。试验结果表明,舍饲波隆杂交羔羊育肥期对象草 玉米型日粮干物质采食量与代谢体重和日增重的关系为：DMI（g/d）=181.3W0.75－0.61ΔW－886.2（r=0.9287）;舍饲波隆杂羔羊育肥期粗蛋白质（CP）、总能（GE）、消化能（DE）需要量的估测模型分别为：CP（g/d）=19.56 W0.75＋0.25ΔW－128.6（r=0.7836）,GE（MJ/d）=2.98 W0.75＋0.023ΔW－18.69（r=0.8257）,DE（MJ/d）=1.26 W0.75－.006ΔW－3.56（r=0.6236）;3~6月龄舍饲育肥期波隆杂羔羊,日粮总能代谢率平均为0.49%,粗蛋白质的消化率平均为0.63%,每增重1 g体沉积蛋白质需要量为0.32 g。     

Calculation of protein and energy requirements in beluga sturgeon (Huso huso) using a factorial approach

This study tried to determine the protein and energy requirements of growing beluga sturgeon Huso huso using a factorial approach. The experiment was composed of four small‐scale growth trails covering different weight ranges. The fish fed at 0, 20, 40, 60, 80 and 100% of satiation. DWG had a steady increase throughout the experiment following a non‐linear equation as Y = 1.433 (±0.056) × Ln(X) ?2.740 (±0.261); r² = 0.99, p < 0.001, where Y = weight gain (g/day) and X = fish weight (g). The daily requirement of digestible energy (DE) for maintenance amounted to 79.09 kJ × BW (kg)^0.8. The daily requirement of DP for maintenance calculated as 0.93 g × BW (kg)^0.7. The relationship between DE intake (X) and DE gain (Y) expressed as Y = ?0.0004 (±0.000) X² + 0.600 (±0.082) X ?44.95 (± 6.72). Also, the relationship between DP intake (X) and protein gain (Y) was expressed as Y = ?0.019 (±0.006) X² + 0.548 (±0.062) X ? 0.498 (±0.121). The daily requirements of energy and protein were estimated as 79.09 kJ × BW (kg)^0.8 + 2.94 × DE gain and 0.93 g × BW (kg)^0.7 + 2.63 × DP gain. Apparently, beluga sturgeon is inefficient in converting energy and protein into body tissue. Therefore, energy content of the diet should be sufficiently high to satisfy large energy demands in beluga sturgeon and also to reduce the catabolism of protein.     

The Effect of increasing levels of date palm (Phoenix dactylifera L.) seed on the performance,ruminal fermentation,antioxidant status and milk fatty acid profile of Saanen dairy goats

This study was conducted to examine the effect of date palm (Phoenix dactylifera L.) seed (DPS) on the performance, ruminal fermentation, antioxidant status and milk fatty acid (FA) profile of dairy goats. Eight multiparous Saanen dairy goats, averaging 97 ± 7 days in milk (DIM) and 2150 ± 130 g of milk production, were used in a 4 × 4 replicated Latin square design. Experimental diets contained 0% (control), 6% (DPS6), 12% (DPS12) and 18% (DPS18) of DPS. Dry matter intake (DMI), milk production, and the composition and digestibility of the dry matter (DM), organic matter (OM), neutral detergent fibre (NDF) and crude protein (CP) were not affected by the diets. Adding DPS to the diet increased linearly total antioxidant capacity (TAC) in milk and blood (p < 0.05). No significant difference was found in the malondialdehyde (MDA) content in milk and blood. Superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) activities in the blood, ruminal pH, NH₃‐N, ruminal total volatile fatty acid (VFA), acetate, butyrate, isovalerate and valeric acid concentration had no significant effect among the diets. The propionate acid concentration decreased linearly as DPS was added to the diet, and DPS18 had minimum propionate acid concentration (p < 0.05). The inclusion of DPS18 to diets increased linearly the proportion of C18:0 (compared to control) as well as cis‐18:1, trans‐18:1 (compared to control and DPS6) and decreased C14:1 (compared to control) in milk fat (p < 0.05). The concentration of conjugated linoleic acid (CLA) in DPS18 was higher than other diets (p = 0.04). The results of this study implied that replacing DPS with a part of dairy goats’ ration had no negative effects on the performance of the animals and could also improve the antioxidant activity and increase the concentration of CLA in their milk.     

不同能量和蛋白水平日粮对西农萨能奶山羊泌乳性能的影响

为筛选西农萨能奶山羊泌乳期全价料最适能量和蛋白水平,选取体重(50.56±0.76)kg、胎次(2～3)、产奶量(2.12±0.10)kg/d相近和分娩日期与体况一致,并处于泌乳高峰期的健康西农萨能奶山羊36只,随机分为6组,每组6只。采用3×2因子随机区组试验设计6种日粮,NE水平为12.64、13.08和13.52MJ/d,CP水平为16.13%和17.82%。试验期84d,共分4个阶段,每阶段21d。结果表明:日粮NE和CP水平对奶山羊DMI和血液生化指标没有显著影响,但存在交互作用,NE 13.52MJ/d和CP16.13%处理组的DMI最高。随日粮NE和CP水平升高泌乳量增加,其中CP提高可显著增加泌乳量(P=0.041);而乳脂肪、乳蛋白、乳糖、干物质和非脂乳固体等乳成分指标则降低,其中CP提高可显著降低乳蛋白(P=0.013)和非脂乳固体(P=0.031);日粮NE和CP水平对奶山羊泌乳性能的影响存在交互作用,NE 13.52MJ/d和CP17.82%时泌乳量最高,而NE 13.08MJ/d和CP16.13%时乳品质最好。综合各项指标并考虑生产实际,得出西农萨能奶山羊泌乳期日粮适宜的NE和CP水平分别为13.08MJ/d和CP16.13%。     

Comparison of two live Bacillus species as feed additives for improving in vitro fermentation of cereal straws

This study was performed in a 2 × 4 factorial arrangement to explore and compare the effects of inclusion of two live Bacillus additives (B. licheniformis and B. subtilis) at four doses (0, 0.25 × 10⁷, 0.50 × 10⁷ and 0.75 × 10⁷ colony‐forming units (cfu)) on in vitro gas production kinetics, fiber degradation, methane production and ruminal fermentation characteristics of maize stover and rice straw by mixed rumen microorganisms in dairy cows. The pH, concentrations of ammonia nitrogen (NH₃‐N) and isovalerate were increased (P < 0.05), while the methane (CH₄) production, ratio of acetate to propionate, and total volatile fatty acids (TVFA) concentration were decreased (P < 0.05) by the supplementation of B. licheniformis compared with that of B. subtilis. Adding B. licheniformis and B. subtilis raised (P < 0.05) or numerically raised the maximum gas production, while decreasing (P < 0.05) or numerically lowering pH and concentrations of most volatile fatty acids. The addition of B. licheniformis increased (P < 0.05) the NH₃‐N concentration but reduced CH₄ production and ratio of acetate to propionate (P < 0.05), while the NH₃‐N concentration was decreased (P < 0.05), and the CH₄ production and ratio of acetate to propionate were increased by that of B. subtilis compared to the control. Results obtained in this research suggest that B. licheniformis would be preferred as a live Bacillus additive in comparison with B. subtilis, and its optimal dose should be 0.25 × 10⁷ cfu/500 mg substrates.