Determination of net energy content of soybean oil fed to growing pigs using indirect calorimetry

The objectives of this experiment were: (i) to determine the net energy (NE) of soybean oil (SBO) fed to growing pigs using indirect calorimetry (IC); and (ii) to evaluate the effects of inclusion rate of SBO on heat production, oxidative status and nutrient digestibility in growing pigs. Eighteen growing barrows were allotted to three diets based on completely randomized design with six replicate pigs (period) per diet. Diets included a corn‐soybean meal basal diet and two test diets containing 5% or 10% SBO at the expense of corn and soybean meal. During each period, pigs were individually housed in metabolism crates for 14 days, including 7 days to adapt to feed, metabolism crate and environmental conditions. On day 8, pigs were transferred to the open‐circuit respiration chambers for measurement of daily O₂ consumption and CO₂ and CH₄ production. During this time, pigs were fed one of the three diets at 2.4 MJ metabolizable energy/kg body weight (BW)^0.6/day. Total feces and urine were collected and daily total heat production (THP) was measured from days 9 to 13 and fasted on day 14 to evaluate their fasting heat production (FHP). The results show that trends of decreased apparent total tract digestibility of neutral detergent fiber (linear, P = 0.09) and acid detergent fiber (linear, P = 0.07) were observed as the content of dietary lipids increased. The average THP for the three diets were 1326, 1208 and 1193 kJ/kg BW^0.6/day, respectively. The FHP of pigs averaged 843 kJ/kg BW^0.6/day and was not affected by diet characteristics. A reduction of the respiratory quotients in the fed state as the inclusion level of SBO increased was observed. In conclusion, the NE values of SBO we determined by indirect calorimetry were 33.45 and 34.05 MJ/kg dry matter under two inclusion levels. THP could be largely reduced when SBO is added in the feed, but the THP of SBO included at 5% in a corn‐soybean meal diet is not different from the THP of SBO included at 10%.     

Comparison of heat production and plasma lipid metabolites between meat- and egg-types of Nagoya breed chicken during embryonic development

We compared heat production (HP) and plasma lipid metabolites between meat‐ and egg‐types of Nagoya breed chickens during embryonic development. To investigate HP and respiratory quotient, oxygen consumption and carbon dioxide production were measured using an open‐circuit calorimeter system. HP was significantly lower in meat‐ than in egg‐type chickens during embryonic development, and HP gradually decreased with developmental stage in both types. The respiratory quotient was constant at approximately 0.68 at every embryonic stage investigated, and the value was similar in both types. Plasma concentrations of triacylglycerol, nonesterified fatty acid, glycerol and D‐3‐hydroxybutyrate, which are associated with lipid metabolism, were similar in both types during embryonic development. These results demonstrate that chicken embryos selected for rapid growth of Nagoya breed have characteristic lower HP, and that when selecting chickens for rapid growth, HP is an important parameter during embryonic stages.     

Net energy of oat bran,wheat bran,and palm kernel expellers fed to growing pigs using indirect calorimetry

The objectives of this experiment were to (a) determine the effects of fiber increase in diets on heat production (HP), (b) determine the net energy (NE) of oat bran (OB), wheat bran (WB), and palm kernel expellers (PKE) fed to growing pigs using indirect calorimetry (IC). Twenty‐four growing barrows (29.2 ± 2.6 kg) were randomly allotted to one of four diets with six replicate pigs per diet. Diets included a corn‐soybean meal basal diet and three test diets containing 30% OB, WB or PKE, respectively. During each period, pigs were individually housed in metabolism crates for 20 days, including 14 days to adapt to the diets. On day (d) 15, pigs were transferred to the open‐circuit respiration chambers for determination of daily total HP and were fed one of the four diets at 2.3MJ ME/kg body weight (BW)^0.6/day. Total feces and urine were collected for the determination of digestible energy (DE) and metabolizable energy (ME) and daily total HP was measured from d 15 to d 19 and fasted on day 20 for the measurement of fasting heat production (FHP). The apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), and organic matter (OM) were greater (p < 0.01) in pigs fed the basal diet compared with those fed the test diets. The ATTD of neutral detergent fiber (NDF) was lower (p < 0.01) in pigs fed the WB diet compared with those fed the basal, OB, or PKE diets. The ATTD of ether extract (EE) in pigs fed the PKE diet was greater (p < 0.01) compared with those fed the other diets. The average total HP and FHP in pigs fed the four diets were 1261 and 787 kJ/kg BW^0.6/d, respectively, and were not significantly affected by diet characteristics. The NE:ME ratio for diets ranged from 78.1 to 80.9%. The NE contents of OB, WB, and PKE were 10.93, 7.47, and 8.71 MJ/kg DM, respectively.     

肉仔鸡生长过程中行为与产热的变化

研究肉仔鸡成长过程中行为变化对产热量的影响 ,将 2日龄肉仔鸡 36只分为自由摄食、 50 %摄食和绝食 3组进行观测。立位行为集中在明期 ,特别是摄食 30min前后 ,暗期几乎没有出现立体行为。 2日龄时 ,每天约有 70 0min是立位的 ,其后 ,随着日龄的增加而减少。在自由采食区 ,公雏比母雏摄食时间长。 50 %摄食区较自由采食区的摄食时间少。在绝食区 ,随着日龄的增加 ,公母的立位时间呈现减少倾向。 2 1日龄之前随着日龄的增加其摄食时间也增加 ,其后呈现相反倾向。产热 (HP ,kJ/kg0 75)与摄食时间有相同倾向。在 2 1日龄前公雏的HP比母雏低 ,2 1日龄后母雏比公雏低。 1天中各个区的HP活动规律是摄食后 1h内最高 ,暗期降低 ;限制摄食量后 ,HP降低 ,明期和暗期的HP差也随之减小     

Effects of high‐fat and high‐carbohydrate diets on fat and carbohydrate oxidation and plasma metabolites in healthy cats

High‐fat (HF) or high‐carbohydrate (HC) diets (30% fat, 18.9% carbohydrate; HF and 10% fat, 46.3% carbohydrate; HC) and lengths of adaptation were investigated in cats (Felis catus; 10 ± 2 months, 3.6 ± 0.3 kg). Cats randomly received each treatment for 14 days in a crossover design with a 14‐day washout period between each diet. Three 22‐h indirect calorimetry studies were conducted after acute (day 0), semichronic (day 4) and chronic (day 13) dietary exposure. Blood samples were collected after a 24‐h fast on days 1, 5 and 14. When cats consumed the HC and HF diet, oxidation of the restricted nutrient exceeded intake while oxidation of the nutrient in excess matched intake. Mean max energy expenditure (EE) of cats consuming the HF and HC diet were 107 and 102 kcal/kg^0.67/day and occurred at a mean of 4 and 12 h post‐feeding respectively. Maximal fat (0.90 g/h) and carbohydrate (carbohydrate; 1.42 g/h) oxidation were attained at 26 min and 10.4 h post‐feeding respectively. The changes observed in macronutrient oxidation and EE suggest that cats adapt whole‐body nutrient metabolism in response to changes in dietary macronutrient content, but may require longer than 14 day to adapt to a macronutrient that is present at a lower concentration in the diet.     

Effects of medium‐chain fatty acid‐cyclodextrin complexes on ruminal methane production in vitro

The purpose of the present study was to evaluate effects of medium‐chain fatty acid‐cyclodextrin (CD) complexes on ruminal methane and volatile fatty acid production, and protozoal activity in vitro. Medium‐chain fatty acid‐CDs used in this study were caprylic acid (C8)‐αCD or ‐βCD, capric acid (C10)‐αCD or ‐βCD, and lauric acid (C12)‐αCD or ‐βCD. A 60‐mL of diluted rumen fluid was incubated anaerobically at 38°C for 6 h with the addition of the complex (10–40 mg as fatty acid). Each of the fatty acid‐CDs reduced the number of protozoa, with the order C10 > C12 > C8, and βCD complexes were more effective than αCD complexes. Molar proportions of acetic acid remained unchanged with the addition of fatty acid‐CD, while that of propionic acid increased, being significant for C8‐αCD and βCD, and C10‐αCD and βCD (P < 0.05). Hydrogen production decreased by about 70% of control with the addition of 40 mg of C8 and C10‐CD, on the other hand, it tended to increase with the addition of C12‐CD in both αCD and βCD. Methane production decreased by about 20% with the addition of 40 mg of complexes, except for C10‐βCD, which significantly reduced methane production by about 60%. In conclusion, the addition of C8 or C10‐CD to ruminant diets may be effective in reducing methane production.     

Effects of pistachio by‐products on digestibility,milk production,milk fatty acid profile and blood metabolites in Saanen dairy goats

The objective of this study was to investigate the effects of pistachio by‐products (PBP) on nutrient digestibility, blood metabolites and milk fatty acid (FA) profile in Saanen dairy goats. Nine multiparous lactating Saanen goats (on day 90 post‐partum, 45 ± 2/kg BW) were randomly assigned to a 3 × 3 Latin square design with three treatment diets: 1) control diet (alfalfa hay based), 2) 32% PBP and 3) 32% PBP + polyethylene glycol (PEG‐4000; 1 g/kg dry matter). Each period lasted 21 days, including 14 day for treatment adaptation and 7 day for data collection. Pistachio by‐products significantly decreased (p < 0.01) crude protein (CP) digestibility compared with the control diet (64.4% vs. 58.7%), but PEG addition did not differ for CP digestibility of goats fed 32% PBP + PEG and those fed the two other diets. The digestibility of NDF tended (p = 0.06) to decrease for goats fed PBP compared with those fed the control diet. Yields of milk and 4% fat‐corrected milk were not affected by dietary treatments. Compared with the control diet, PBP supplementation appreciably changed the proportions of almost all the milk FA measured; the main effects were decreases (p < 0.01) in FA from 8:0 to 16:0 and increases (p < 0.01) proportions of cis‐9, trans‐11 18:2 and trans‐11 18:1, monounsaturated FA, polyunsaturated FA and long‐chain FA. The saturated FA, short‐chain FA and medium‐chain FA proportions were lower (p < 0.01) in goats fed the two PBP supplemented diet than in those fed the control diet and PEG addition led to intermediate proportions of saturated FA, unsaturated and monounsaturated FA. Inclusion of PBP in the diet decreased (p < 0.01) plasma concentrations of glucose and urea nitrogen compared with the control diet. It was concluded that PBP can be used as forage in the diet of dairy goats without interfering with milk yield. Inclusion of 32% PBP in the diet of dairy goats had beneficial effects on milk FA profile but PEG addition to PBP did not contribute to enhance further milk FA profile.     

Effect of prepubertal nutrition on cellular apoptosis and proliferation in at term placenta of Anglo‐Nubian goats

The aim of this study was to evaluate the effect of feed restriction with or without monensin supplementation, followed by a re‐feeding period on cellular apoptosis and proliferation in at term placenta of Anglo‐Nubian goats. To evaluate the induction of apoptosis through the intrinsic pathway, proteins Bax and Bcl‐2 were determinated. The apoptosis was related with the cell proliferation indices through Ki67 determination. The treatments were applied for 250 days and were (a) ad libitum feeding (control; n = 5); (b) restricted feeding at 70% of control (restricted; n = 7); and (c) restricted with monensin supplementation (monensin; n = 7). After treatments, all the animals were fed to support their requirements. After parturition, 27 placentas were gathered. The placental cellular structure was studied by high‐resolution light microscopy and transmission electron microscopy; the cellular proliferation was determined by Ki67 index, and Bax and Bcl‐2 proteins were localized by immunohistochemical analysis. Differences in cell proliferation through the Ki67 index were found in monensin group placentas. Monensin supplementation stimulated the placental cell proliferation reversing the effect of feed restriction during the peripuberal period. A significant increase of Bcl‐2 in placentas of restricted group was found, and it would provide a protective effect on the placental structure. A lack of the Bcl‐2 protective effect was observed in control and monensin group placentas, probably meaning that the observed apoptosis would be induced through the intrinsic signalling pathway. A balance between apoptosis and cell proliferation is necessary to maintain tissue homoeostasis during caprine placental development.     

Thermal decomposition,chemical composition,in vitro digestibility and gas production and in situ degradability of oilseed residues from the biofuel industry

Thermal analysis could rapidly and easily predict nutritional value of ruminant feeds. The hypothesis is that crambe meal (CM) has a quality similar to that of soybean meal (SM), and the objective of this study was to determine the nutritional characteristics of CM and compare them to those of SM. CM had greater concentrations of phytic acid (26.3 vs. 16.0 g/kg) and phenol compounds (615 vs. 393 mg gallic acid (GAE)/kg) than SM. In vitro dry matter (DM) digestibility was lower for CM than SM (752 vs. 975 g/kg DM). Cumulative in vitro gas production at 48 h of incubation (14.1 vs. 19.4 mL/100 mg substrate DM), and energy release (4.5 vs. 5.7 kJ/g substrate DM) were lower for CM than SM. CM had a higher concentration of low digestible fiber, hence degradability of DM was lower and the proportion of indigestible fraction was greater for CM than SM. High concentrations of indigestible compounds were likely responsible for lower gas production of CM compared to SM. These results suggest CM quality is lower than that of SM and that thermal analysis is a useful tool to precisely determine the nutritive value of oilseed residues.     

Effect of treating alfalfa silage with pistachio by‐products extract on Saanen dairy goats performance and microbial nitrogen synthesis

A lactation experiment was conducted to determine the influence of addition of pistachio by‐products extract (PBE) to alfalfa silage (AS) on performance, rumen fermentation, milk yield and composition, and microbial nitrogen synthesis. Eight multiparous dairy goats (1.8 ± 0.25 kg of milk yield) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments to compare two types of AS (supplemented with or without PBE) with two levels of dietary crude protein (14% vs. 16% CP). Dietary treatments were (i) AS with 14% CP of DM diet without PBE (14%CP?PBE), (ii) AS with 14% CP of DM diet with PBE (14%CP + PBE), (iii) AS with 16% CP of DM diet without PBE (16%CP?PBE) and (iv) AS with 16% CP of DM diet with PBE (16%CP + PBE). PBE was sprayed on fresh alfalfa at a ratio of 500 ml/kg alfalfa DM to get the final concentration of 1% tannin as tannic acid equivalent on DM basis. Intake of CP was greater (p < 0.01) in goats fed 16% CP diets than those fed 14% CP diets, regardless of PBE supplementation. Supplementation of PBE tended to decrease (p = 0.09) rumen NH₃‐N concentration regardless of the level of CP in the diet. Supplementation of PBE tended (p = 0.09) to decrease total purine derivatives regardless of the level of CP in the diet with no significant change in microbial nitrogen supply. Efficiency of microbial nitrogen synthesis (EMNS) had a tendency (p = 0.07) to decrease in PBE supplemented diets. There was also a tendency (p = 0.10) for more EMNS in 14% CP fed goats than those fed 16% CP diets. Therefore, AS supplemented with PBE may lead to less concentration of ruminal NH₃‐N because of decreased degradation of CP by rumen micro‐organisms in response to pistachio by‐products tannins.     

甜菜碱和酵母铬对高温环境中肉牛生产性能的影响

本试验旨在研究甜菜碱和酵母铬对高温环境中肉牛生产性能的影响。试验选择32头胎次相同、体重相近的中国西门塔尔牛,随机分为4组,对照组饲喂基础日粮,试验1组、2组和3组在基础日粮的基础上分别添加21 g/d.头的甜菜碱,0.8 mg/kg酵母铬,以及21 g/d.头甜菜碱和0.8 mg/kg酵母铬的混合物。试验期为42 d,结果表明:(1)添加甜菜碱和酵母铬对肉牛的呼吸频率和直肠温度影响不明显(P>0.05);(2)与对照组相比,试验1组肉牛采食量提高了17.22%,试验3组提高了4.38%,试验2组降低了1.81%,但均不显著(P>0.05);与对照组相比,试验1组,2组和3组日增重分别提高39.66%、31.03%和8.93%(P>0.05);料肉比试验1组,2组和3组分别比对照组降低16.04%、25.07%(P<0.05)和0.79%。     

Extent and economic effect of heat loads on dairy cattle production in Australia

OBJECTIVE: To investigate the extent of heat load problems, caused by the combination of excessive temperature and humidity, in Holstein-Friesian cows in Australia. Also, to outline how milk production losses and consequent costs from this can be estimated and minimised. PROCEDURES: Long-term meteorological data for Australia were analysed to determine the distribution of hot conditions over space and time. Fifteen dairy production regions were identified for higher-resolution data analysis. Both the raw meteorological data and their integration into a temperature-humidity thermal index were compiled onto a computer program. This mapping software displays the distribution of climatic patterns, both Australia-wide and within the selected dairying regions. Graphical displays of the variation in historical records for 200 locations in the 15 dairying regions are also available. As a separate study, production data from research stations, on-farm trials and milk factory records were statistically analysed and correlated with the climatic indices, to estimate production losses due to hot conditions. RESULTS: Both milk yields and milk constituents declined with increases in the temperature-humidity index. The onset and rate of this decline are dependent on a number of factors, including location, level of production, adaptation, and management regime. These results have been integrated into a farm-level economic analysis for managers of dairy properties. CONCLUSION: By considering the historical patterns of hot conditions over time and space, along with expected production losses, managers of dairy farms can now conduct an economic evaluation of investment strategies to alleviate heat loads. These strategies include the provision of sprinklers, shade structures, or combinations of these.     

Effect of Heat Stress on Milk Production,Rectal Temperature,Respiratory Rate and Blood Chemistry in Holstein,Jersey and Australian Milking Zebu Cows

The effect of heat stress on changes in milk production, rectal temperature, respiratory rate and blood chemistry was evaluated in three groups of six mature Holstein, Jersey and Australian Milking Zebu (AMZ) dairy cows. These animals were subjected to a cool environment when the mean temperature-humidity index (THI) was 72+/-1.4 (dry bulb temperature of 22.2-24.4 degrees C and relative humidity of 100-60%) during the month of December. This experiment was repeated during the hotter month of July of the following year, when the mean THI was 93+/-3.1 (dry bulb temperature of 35.6-43.9 degrees C and relative humidity 95-35%). Holstein cows produced more (p <0.01) milk than AMZ and Jersey cows during the cooler months of the year and all the cows were dry during the hotter months from June until September. Heat stress increased (p<0.01) rectal temperature and respiratory rate in all three breeds. Heat stress had no effect on blood pH in Holstein and AMZ cows but lowered (p <0.01) blood pH from 7.42 to 7.34 in Jersey cows. In addition, heat stress lowered (p <0.01) blood pCO2 (kPa), bicarbonate (HCO3, mmol/L), base excess (BE, mmol/L) and plasma chloride (Cl-, mmol/L) in all three breeds. The total haemoglobin (THb, g/dl) was elevated (p <0.01) in all three breeds when they were subjected to heat stress. Heat stress increased (p<0.01) oxygen saturation (O2SAT, %) in Jersey and AMZ cows but lowered it (p <0.01) in Holstein cows. On the other hand, heat stress increased (p <0.01)pO2 (kPa) in Holstein and Jersey cows but lowered it (p <0.01) in AMZ cows. Heat stress increased (p <0.01) plasma potassium (K, mmol/L) and calcium (Ca, mmol/L) only in Holstein and Jersey cows but lowered them (p<0.01) in AMZ cows. The plasma glucose (GLU, mmol/L) increased (p<0.01) with heat stress in Holstein and AMZ cows but decreased (p <0.01) in Jersey cows. Heat stress increased (p<0.01) plasma creatinine (CR, (mol/L) but lowered (p<0.01) plasma creatinine phosphokinase (CPK, IU/L), aspartate aminotransferase (AST, IU/L) and blood urea nitrogen (BUN, mmol/L) in all three breeds. These results indicate that heat-stressed Holstein and AMZ cows were able to maintain their acid-base balance with a marginal change in their pH of 0.02 when their rectal temperatures increased by 0.47 and 0.38 degrees C, respectively. When heat stress increased the rectal temperature in Jersey cows by 0.70 degrees C, the pH decreased (p<0.01) from 7.42 to 7.34. However, even with this decrease 0.08 the pH is still within the lower physiological limit of 7.31.     

Prokaryotic expression of chicken interferon‐γ fusion protein and its effect on expression of poultry heat shock protein 70 under heat stress

Interferons have attracted considerable attention due to their vital roles in the host immune response and low induction of antibiotic resistance. In this study, total RNA was extracted from spleen cells of chicken embryos inoculated with Newcastle disease vaccine, and the full‐length chicken interferon‐γ (ChIFN‐γ ) gene was amplified by RT‐PCR. The full complementary DNA sequence of the ChIFN‐γ gene was 495 bp long and was cloned into the prokaryotic expression vector pProEX?HT_b. The plasmid was transformed into Escherichia coli DH5α and the expression of ChIFN‐γ was induced by isopropyl β‐D‐1‐thiogalactopyranoside. Sodium dodecyl sulfate – polyacrylamide gel electrophoresis and Western blot results showed the expressed fusion protein had a molecular weight of approximately 18 kDa and was recognized by an anti‐His mAb. Moreover, ChIFN‐γ was found to demonstrate anti‐viral activity in vitro . To test the in vivo function of ChIFN‐γ in broilers under heat stress, a total of 100 broilers were randomly assigned to either a control group or a treated group, in which they were hypodermically injected with recombinant ChIFN‐γ. Results demonstrated ChIFN‐γ affects the messenger RNA expression levels of heat shock protein 70 (HSP70) in the heart and lung tissues, and decreases the concentration of HSP70 in serum. Therefore, we conclude recombinant ChIFN‐γ can reduce heat stress to some extent in vivo .     

Evaluation of a single‐flow continuous culture fermenter system for determination of ruminal fermentation and enteric methane production

A 4‐unit, single‐flow continuous culture fermenter system was developed to assess in vitro nutrient digestibility, volatile fatty acid (VFA) concentration and daily enteric methane (CH₄) production of ruminant diets. The objective was to develop a closed‐vessel system that maintained protozoal populations and provided accurate predictions of total CH₄ production. A diet of 50% orchardgrass (Dactylis glomerata L.) and 50% alfalfa (Medicago sativa L.) was fed during 4, 10‐day periods (7‐day adaptation and 3‐day collection). Fermenters were fed 82 g of dry matter (DM)/day in four equal feedings. pH and temperature were taken every 2 min, and CH₄ concentration was measured every 10 min. Samples for DM and protozoal counts were taken daily, and daily effluent samples were collected for determination of DM, VFA and NH₃‐N concentrations. There was no effect (p > 0.17) of adaptation versus collection days on vessel and effluent DM, temperature or pH. Initial protozoal counts decreased (p < 0.01), but recovered to initial counts by the collection period. Total VFA, acetate, propionate and isobutyrate concentrations did not differ (p ≥ 0.13) among periods or days of the collection period. There was no difference (p ≥ 0.37) among days or periods in total daily CH₄ production and CH₄ production per g of OM, NDF, digestible OM or digestible NDF fed. Data collected throughout 4 experimental periods demonstrated that the system was able to reach a steady state in fermentation well within the 7‐day adaptation period and even typically variable data (i.e., CH₄ production) were stable within and across periods. While further research is needed to determine the relationship between this system and in vivo data, this continuous culture fermenter system provides a valid comparison of in vitro ruminal fermentation and enteric CH₄ production of ruminant diets that can then be further validated with in vivo studies.     

The effect of dietary Chlorella vulgaris supplementation on micro‐organism community,enzyme activities and fatty acid profile in the rumen liquid of goats

Microalgae might be considered as an alternative source of fat and/or protein for ruminant's diets. However, changes in populations of ruminal micro‐organisms associated with biohydrogenation process, methane and ammonia production in response to microalgae dietary supplementation have not been well characterized. Thus, 16 cross‐bred goats were divided into two groups. Each goat of both groups was fed individually with alfalfa hay and concentrates separately. The concentrates of the control group had no microalgae while those of the treated group were supplemented with 10 g lyophilized Chlorella vulgaris/kg concentrate (chlor). On the 30th experimental day, samples of rumen fluid were collected for microbial DNA extraction, fatty acid profile and enzyme activity analyses. The results showed that the chlor diet compared with the control increased significantly the populations of Methanosphaera stadtmanae, Methanobrevibacter ruminantium and Methanogens bacteria and protozoa in the rumen of goats. A significant reduction in the cellulase activity and in the abundance of Ruminococcus albus, and a significant increase in the protease activity and in the abundance of Clostridium sticklandii in the rumen liquid of goats fed with the chlor diet, compared with the control, were found. Chlorella vulgaris supplementation promoted the formation of trans C_18:1, trans‐11 C_18:1 and monounsaturated fatty acids (MUFA), while the proportions of C_18:0 and long‐chain fatty acids (LCFA) reduced significantly in the rumen liquid of goats. This shift in ruminal biohydrogenation pathway was accompanied by a significant increase in Butyrivibrio fibrisolvens trans C_18:1‐producing bacteria. In conclusion, the supplementation of diets with microalgae needs further investigation because it enhances the populations of methane‐producing bacteria and protozoa.     

Methane production from thermophilic co‐digestion of dairy manure and waste milk obtained from therapeutically treated cows

Methane production from co‐digestion of dairy manure and waste milk, milk from cows treated with antibiotics for mastitis, was tested in a 2 × 4 factorial design. Four different waste milk percentages (w/w): 0% (SM), 10% (SMWM10), 20% (SMWM20) and 30% (SMWM30), were tested with two slurry percentages (w/w): 50% (A) and 25% (B) and the rest being manure at 55°C for 12 days in batch digesters. The results analyzed using a Gompertz model showed SMWM10 produced the highest methane production potential (P_m)/g volatile solids added followed by SM in both A and B. This P_m of SMWM10 in A and B was statistically non‐significant (P > 0.05). More than 96% of cefazolin‐resistant bacteria and 100% of multi‐drug‐resistant bacteria reductions were observed in all the treatments. Inclusion of waste milk at 10% in single stage digester enhances the methane production from dairy manure and could offer added benefit of waste milk treatment and disposal.     

The effects of early‐age thermal manipulation and daily short‐term fasting on performance and body temperatures in broiler exposed to heat stress

This study was conducted to investigate the effects of thermal manipulation at 5 days of age and short‐term fasting during the warmest part of the day on responses to prolonged heat stress of broilers. A total of 240‐day‐old Ross 308 female broiler chicks were divided into three groups: control, thermal manipulation (chicks were exposed to 36 °C for 24 h at 5 days of age) and short‐term fasting during the warmest part of the day (10.00–17.00 h). Prolonged heat stress was induced daily from 28 to 42 days by heating until the ambient temperature reached 32–35 °C between 10.00 and 17.00 h. Both thermal manipulation and short‐term fasting resulted in a decrease in rectal temperatures and haematocrit values at 35 and 41 days of age. Thermal manipulation improved body weight, feed consumption and feed conversion. However, short‐term fasting caused a reduction in body weight and a deterioration in feed conversion. Short‐term fasting lowered the percentages of carcass, whereas thermal manipulation highered breast yield. Both thermal manipulation and short‐term fasting decreased heart mass and abdominal fat.     

Dietary supplementation of Zingiber officinale and Zingiber zerumbet to heat‐stressed broiler chickens and its effect on heat shock protein 70 expression,blood parameters and body temperature

The present study was conducted to assess the effects of dietary supplementation of Zingiber officinale and Zingiber zerumbet and to heat‐stressed broiler chickens on heat shock protein (HSP) 70 density, plasma corticosterone concentration (CORT), heterophil to lymphocyte ratio (HLR) and body temperature. Beginning from day 28, chicks were divided into five dietary groups: (i) basal diet (control), (ii) basal diet +1%Z. zerumbet powder (ZZ1%), (iii) basal diet +2%Z. zerumbet powder (ZZ2%), (iv) basal diet +1%Z. officinale powder (ZO1%) and (v) basal diet +2%Z. officinale powder (ZO2%). From day 35–42, heat stress was induced by exposing birds to 38 ± 1 °C and 80% RH for 2 h/day. Irrespective of diet, heat challenge elevated HSP70 expression, CORT and HLR on day 42. On day 42, following heat challenge, the ZZ1% birds showed lower body temperatures than those of control, ZO1% and ZO2%. Neither CORT nor HLR was significantly affected by diet. The ZO2% and ZZ2% diets enhanced HSP70 expression when compared to the control groups. We concluded that dietary supplementation of Z. officinale and Z. zerumbet powder may induce HSP70 reaction in broiler chickens exposed to heat stress.