Effects of dietary mineral supplementation on the performance and mineral retentions of broilers at high ambient temperatures

1. The relationship between broiler performance and two dietary mineral balance equations was investigated at a high constant ambient temperature (30°C) using a range of 11 salt supplements given to male broiler chicks from 21 to 42 d of age.

2. No relationship was found between broiler performance and either of the two balance equations.

3. Re‐evaluating these equations using retained, rather than dietary, mineral concentrations did not improve the relationship although changes in mineral retentions associated with the supplements indicated that dietary concentrations were not a good indicator of the impact of the diet on the bird's acid‐base homoeostasis.

4. Evidence was found that metabolisable anions supplemented in association with mineral cations may have a significant effect on broiler performance.     

Effect of concentrate extrusion and castration on diet digestion and performance of intensively reared male calves

Fifty-six male Friesian calves, half of them castrated, were used to study the effects of concentrate extrusion and animal castration on diet digestibility and performance in two different growth phases (from 91 to 250 and from 250 to 400 kg live weight). Diets consisted of a compound meal, extruded or nonextruded, and barley straw, both of them fed ad libitum. Half of the animals were slaughtered at 250 kg and the remaining at 400 kg live weight. Extrusion increased the gelatinization grade, resulting in a higher (p<0.01) fermentation rate, and reduced nitrogen solubility and degradation after 12 h of rumen incubation (p<0.05). Calves receiving the extruded meal showed a lower rumen ammonia concentration just before the first meal (p<0.001), the differences disappearing afterwards. Neither the pH nor the total VFA concentrations were affected, although butyrate, isobutyrate and isovalerate proportions before the first meal decreased with the extruded diet. Concentrate extrusion did not affect the apparent OM digestibility of total diet but caused a reduction of NDF (p<0.01) and CF (p<0.05) digestibility. In the first growth phase, concentrate and total DM intake decreased with extrusion (p<0.001), without affecting the average daily gain (ADG). Consequently, the concentrate and total feed conversion ratios were significantly lower (p<0.001 and p<0.01, respectively) with the extruded meal. Bulls showed a higher ADG than steers (p<0.001), resulting in lower feed conversion ratios (p<0.01) given that intake was not affected by castration. In the second growth phase, extrusion did not affect any of the performance parameters, however bulls showed a higher DM intake and ADG (p<0.05), but no differences in the feed conversion ratio were found between entire and castrated animals.     

Effects of 'Five freedoms' environmental enrichment on the welfare of calves reared indoors

We provided comfortable resting areas in pens and tools for self-grooming and suppressing aggressive behavior for environmental enrichment in Japanese black and Japanese Shorthorn calves. At the start of the experiment, the black calves ( n  = 10) were 164 days old and 138 kg in weight, and the Japanese Shorthorn calves ( n  = 10) were 176 days old and 164 kg in weight. Calves of each breed were divided into two groups (the enrichment group and the non-treatment group), and each group was housed in a 4 m × 7.2 m pen. The effect of enrichment on calf welfare was estimated on the basis of daily weight gain and behavior. The brush stimulated the grooming behavior in calves although the mean time of using the brush decreased during the experiment. The partition of the feed trough and the wooden wall in the pen decreased the agonistic behavior in Japanese Shorthorn calves ( P  < 0.01) and increased the affiliative behavior in Japanese black calves ( P  = 0.08). The cleanliness of the bedding increased sternum lying and lying with the head touching the flank or ground in Japanese black calves and decreased the standing resting behavior in both breeds ( P  < 0.05 in all the cases). However, the treatments did not have an effect on daily weight gain. We concluded that the treatments would improve the welfare of calves and function as environmental enrichments.     

Efficiency of effect of high ambient temperatures on food utilisation in male broilers

The effect of ambient temperatures above 28 degrees C on the efficiency of food utilisation were studied in 7 consecutive flocks of male broilers, grown in a cross-ventilated controlled environment poultry house. The best correlation between the food:gain ratio and temperature was obtained when the latter was expressed as degrees-h (Th), that is, the aggregate of the differences between the ambient temperature and 28 degrees C, measured hourly. The equation: Food:gain ratio = 2072 + 0.125 X Th, demonstrates clearly the negative effect of high temperatures on food:gain ratio in broilers. It might be helpful for the broiler industry when evaluating the need for and planning of cooling devices for poultry houses.     

Influence of high ambient temperatures on performance of multiparous lactating sows.

Multiparous Large White sows (n = 63) were used to investigate the effects of five ambient temperatures (18, 22, 25, 27, and 29 degrees C) and two dietary protein contents on their lactation performance. At each temperature treatment, ambient temperature was maintained constant over the 21-d lactation period. Dietary protein content was either 14 or 17% with essential amino acids levels calculated not to be limiting. The animals had ad libitum access to feed between the seventh and the 19th day of lactation. Diet composition did not influence lactation performance. Over the 21-d lactation, feed intake decreased from 5.67 to 3.08 kg/d between 18 and 29 degrees C. Between d 7 and 19, the corresponding values were 7.16 and 3.48 kg/d, respectively. This decrease was curvilinear; an equation to predict voluntary feed intake (VFI) from temperature (T, degrees C) and body weight (BW, kg) is proposed: VFI = -49,052 + 1,213 T - 31.5 T2 + 330 BW - .61 BW2 (residual standard deviation: 1,018). Skin temperature increased regularly with increased ambient temperature (34.6 to 37.4 degrees C between 18 and 29 degrees C), whereas udder temperature reached a plateau at 25 degrees C (38.3 degrees C). The gradient of temperature between skin and rectum was minimal (2 degrees C ) at 27 degrees C and remained constant at 29 degrees C. This constancy coincides with the marked reduction of feed intake. The respiratory rate increased from 26 to 124 breaths/min between 18 and 29 degrees C, and this indicates that the evaporative critical temperature was below 22 degrees C. The BW loss increased from 23 to 35 kg between 18 and 29 degrees C, but its estimated chemical composition remained constant. Pig growth rate was almost constant between 18 and 25 degrees C (241 g/d) and was reduced above 25 degrees C (212 and 189 g/d at 27 and 29 degrees C, respectively). In conclusion, temperatures above 25 degrees C seem to be critical for lactating sows in order to maintain their performance.     

Effects of chilled drinking water on the performance of lactating sows and their litters during high ambient temperatures under farm conditions

Heat stress has detrimental effects on lactating sows and their litters, including decreased feed intake and milk production in sows and decreased weight gain in their offspring. It also increases respiration rate, rectal temperature, and weaning to estrus interval in sows. This study was conducted to investigate the effects of chilled water (CW) on the performance of lactating sows and their litters exposed to high ambient temperatures for 21 days. Ninety multiparous sows (Yorkshire × Landrace; parity range: 2 to 5) and their litters (Yorkshire × Landrace × Duroc) were divided into 3 blocks (30 each). Sows and their litters within each block were randomly assigned to one of the three treatment groups (n = 10 each). Each group was provided with drinking water at 10, 15, or 22 °C (control) under farm conditions where ambient temperature above 25 °C was consistent during the experimental period. Sows on CW (both 10 and 15 °C) consumed more feed and water than did control (P < 0.01) and higher estimated milk production compared with control (P < 0.01), but had lower rectal temperature and respiration rate compared with control (P < 0.01). Mean weaning weight (P < 0.01) and average daily gain (P < 0.01) of litters in CW groups were higher than those in control group. There were no differences in the measured variables, with the exception of the respiration rates, between the two CW treatment groups. These results suggest that CW may improve the performance of sows and their litters exposed to high ambient temperatures and the 15 °C water, from an energy viewpoint, may be more effective.     

Effects of dietary supplementation of Acanthopanax senticosus on gastrointestinal tract development in calves

Twenty‐four newborn Holstein dairy male calves (with initial body weight of 38 ± 3.0 kg) were used in a randomized block design experiment to determine effects of dietary supplementation of Acanthopanax senticosus (AS) on gastrointestinal tract development. Calves were fed milk (10%/body weight) three times at 06.00, 12.00 and 18.00 hours daily with one to four treatments during the experimental periods (4 to 28 days): no supplementation of AS (control group, CG); 1.0 g/L?time of micro‐powder AS (MP); 1.0 g/L?time of superfine powder AS (SP); or 1.0 g/L?time of coarse powder AS (CP). On days 7, 14, 21 and 28, 20 mL blood samples were collected at 06.00 hours before the morning feeding. At the end of the trial (28 days), all calves were euthanized, and tissue samples were taken and placed in 4% buffered formaldehyde for analyses. In the rumen of MP treatment, compared with the CG treatment, wall thickness and papillae diameter was both significantly lower (P <0.05), while crypt depth was significantly greater (P <0.05). In the duodenum, villi diameter of AS supplemented treatments was significantly lower than that of CG treatment (P <0.05) . Results indicate that calves during sucking period supplemented with AS as MP style could promote gastrointestinal development.     

补铬对高温环境下蛋鸡的产蛋及其血象的影响

用处于高温环境下的 1 92只 34周龄新罗曼 (NewLohmann)蛋鸡为试验对象 ,研究玉米 小麦 豆粕型基础饲粮中添加 0 ,1 0 ,2 0 ,30 ,40和 50mg/kgGTF预混剂对蛋鸡产蛋及其血象的影响。试验鸡随机分为 6组 ,试验期 52d。结果表明 ,与对照组相比 ,补铬蛋鸡产蛋率提高(P >0 0 5) ,料蛋比 (P >0 0 5)降低 ,红细胞 (RBC)数量增多 (P >0 0 5) ,白细胞 (WBC)中淋巴细胞和单核细胞的比例上升 (P >0 0 5) ;异嗜性粒细胞比例下降 (P >0 0 5) ,异嗜性粒细胞与淋巴细胞的比值 (H/L)也呈现下降趋势 (P >0 0 5)。说明铬在一定程度上可提高高温应激蛋鸡的生产性能和免疫机能 ,具有缓解高温应激的作用。     

Effects of copper supplementation on the copper status of peripartum beef cows and their calves

The effects of copper supplementation on the copper status of 40 late-pregnant Aubrac beef cows grazing a copper-deficient pasture and later fed a marginally deficient diet were studied for five months. They were divided into four equal groups; the control group received no copper supplement, groups 1 and 2 received copper as copper sulphate at 10 and 30 mg/kg of diet dry matter (DM), respectively, for five months, and group 3 received 120 mg/kg of diet dry matter for 10 days. Plasma copper concentration and the activity of erythrocyte superoxide dismutase (eSOD) were measured at the beginning of the experiment, in the cows and calves during weeks 1 and 3 after calving, and in the calves before they were turned out to pasture at a mean (sd) age of 51 (26) days. In spite of the low dietary copper content (4.2 mg/kg of DM), the plasma copper concentration of the control cows increased during the winter. All the copper supplements resulted in normal and similar plasma copper concentrations in the cows after calving, but the concentration decreased slightly between weeks 1 and 3 after calving in the group supplemented for 10 days. The treatments did not affect the eSOD of the cows. The calves born to the four groups showed the same patterns of plasma copper and eSOD. Compared with the cows, the calves had low plasma copper concentrations at week 1 and values in the normal range at week 3; their eSOD was high at weeks 1 and 3 but decreased after week 3.     

Effects of supplementation with cellooligosaccharides on growth performance of weaned calves on pasture

We conducted two feeding experiments to evaluate the effects of cellooligosaccharide (CE) supplementation on growth performance in grazing beef calves. Calf sex and age and duration of the experimental period differed between the experiments. Experiment 1 (10 weeks) used 5.6‐month‐old castrated males; Experiment 2 (13 weeks) used 3.9‐month‐old females. Eight Japanese Black calves were assigned to either a control group (CON) or an experimental group (CE) fed CE at a rate of 10 g/day mixed with concentrate. Calves were stocked in fields in which Kentucky bluegrass was dominant. In both experiments, average daily gain tended to be greater in CE than in CON, especially in late stages of experiments, but no significant differences in body weight changes were observed. In Experiment 2, final heart girth was larger in CE than in CON calves. We monitored rumen microbial community composition in Experiment 2 and found increases in fibrolytic bacteria and methanogenic archaea in CE calves, but the overall microbial composition did not differ between the groups. Our results suggest that supplementation with CE may positively affect growth performance in weaned calves on pasture, but longer‐term CE supplementation may be required to exhibit the effect.     

The effects of food withdrawal and darkening on lipid peroxidation of laying hens in high ambient temperatures

The aim of this study was to investigate the effects of feed withdrawal and darkening on the antioxidative status of laying hens in high ambient temperatures between 30-40 degrees C. We determined vitamins A and E, lipid peroxidation as thiobarbituric-acid reactive substances (TBARS), glutathione peroxidase (GSH-Px) and reduced glutathione (GSH) in the serum, liver and muscle. Sixteen week old hens (Ross Brown) were divided into 3 groups of 30 hens each. The first group was used as a control. Hens in the second (feed withdrawal) group were subjected to feed removal between 14-18 h during the summer. Hens in the third (darkening) group were subjected to darkening of the hens house with black curtains between 14-18 h. At the end of 16 weeks, blood serum, liver and breast muscle samples were taken from all animals and analysed. Vitamins A and E levels in serum and liver were significantly (P < 0.05, P < 0.01) higher in feed withdrawal and darkened groups than in control group whereas the serum levels of the darkening group were highest. GSH-Px activity and GSH level in liver and muscle were also significantly (P < 0.05, P < 0.01) higher in feed withdrawal and the darkening group than in control. However, TBARS levels in liver and muscle were significantly (P < 0.05, P < 0.01) lower in feed withdrawal and darkening groups compared with control group, whereas the level of the darkening group was the lowest. In conclusion, we observed that feed withdrawal and darkening of hens in high temperatures during summertime resulted in an increase of antioxidant enzymes and vitamins levels and in a decrease of lipid peroxidation.     

Linseed oil supplementation in diet for horses: Effects on palatability and digestibility

Feed palatability and in vivo apparent digestibility of nutrients were compared in horses fed concentrates in which barley was, or not, partially substituted by 8% linseed oil. According to a cross-over design, three geldings and one stallion were fed at near maintenance level hay plus low or high fat diet (50/50). The last days of each 3-months sub-periods, partial faeces collections were performed and concentrate intake rate was measured to estimate the digestibility and the palatability of the diet. The inclusion of linseed oil did not affect the palatability of the diet and increased significantly (P < 0.05) the apparent digestibility of DM (66.5 vs 64.1%), CF (83.7 vs 57.3%) and NDF (53.0 vs 50.7%) but not of CP and ADF.     

Effect of dietary concentrate level on body immune response in calves fed a wheat straw-based diet

Twenty 9-month-old crossbred calves were divided into 2 equal groups (A and B; n = 10). The feeding trial was conducted for 119 days to study the effect of concentrate supplementation on body immune response and blood metabolites in calves. The concentrate and roughage (wheat straw) ratio in the diet of Groups A and B was 60:40 and 30:70, respectively. Daily dry matter intake was significantly (P<0.01) higher in Group A than in Group B, which also resulted in significantly higher (P<0.01) total body weight gain in the former group. Protein, albumin, globulin, total and differential leukocyte count in blood were similar in the 2 groups but blood glucose level was higher (P<0.05) in the calves of Group A. There was no difference in body immune response between the groups, which indicated that body immune response of animals is not significantly influenced by restricted concentrate feeding.     

Effects of ambient temperature and scrotal fleece cover on scrotal and testicular temperatures in rams.

The objective was to determine scrotal and testicular temperatures in rams and how they are affected by ambient temperature (10 degrees C vs 25 degrees C) and scrotal fleece (densely fleeced vs shaved). Scrotal surface temperatures (SST) of the caudal aspect of the shaved hemi-scrotum at 10 degrees C vs 25 degrees C were (mean, degrees C) 28.9 and 30.5 (P < 0.03), 28.2 and 29.6 (P < 0.04), and 26.1 and 27.6 (P < 0.06) at the top, middle and bottom of the testis, respectively. Scrotal subcutaneous temperatures (SQT) on the fleeced vs shaved side were 33.5 and 32.0 (P < 0.02), 32.2 and 31.1 (P < 0.06), and 31.7 and 30.8 (P < 0.09) at the top, middle, and bottom at 10 degrees C; they were 33.9 and 32.1 (P < 0.02), 33.1 and 31.9 (P < 0.05), and 32.5 and 32.0 (P < 0.15) at 25 degrees C. Intratesticular temperatures (ITT; measured only at 25 degrees C) on the fleeced vs shaved side were 35.3 and 35.0 (P < 0.5), 35.5 and 35.2 (P < 0.4), and 35.4 and 35.0 (P < 0.3) at the top, middle, and bottom. Temperature gradients (difference from top to bottom) were greatest for SST (2.8 degrees C), moderate for SQT (1.8 to 0.1 degrees C), and not significant for ITT (-0.1 and 0.1 degrees C). The SST was approximately 1.5 degrees C warmer at all 3 locations at 25 degrees C vs 10 degrees C. Increased ambient temperature affected SQT more at the bottom than at the top. Conversely, the difference in SQT between the fleeced and shaved sides was greatest at the top. The difference in ITT (0.3 degrees C warmer on the fleeced vs the shaved side at all locations) was not significant. Therefore, the magnitude of temperature increase associated with ambient temperature or scrotal fleece was affected by both depth and vertical location.     

添加不同油脂对肉鸡生长性能的影响

本文旨在研究饲喂不同油脂对肉鸡生长性能及油脂酸价对采食量和体重的影响。试验选用1日龄罗斯308商品肉仔鸡2100只,随机分为7个处理组,每个组10个重复。处理1组添加豆油,处理2组添加鸡鸭油,处理3组添加精炼混合油A(酸价1 mgKOH/g),处理4～6组分别添加不同酸价的劣质混合油A、B和C(酸价分别为8、35 mgKOH/g和53 mgKOH/g),处理7组添加劣质脂肪酸。结果表明,日粮添加劣质脂肪酸组可显著增加8～21、36～42日龄及1～42日龄肉鸡日采食量和料肉比(P<0.05)。劣质混合油C组8～21日龄肉鸡的采食量显著低于其他处理组;而与豆油组比,劣质混合油B和C组8～21日龄肉鸡日增重和21日龄体重显著降低。混合油的酸价与肉鸡采食量及42日龄体重呈负相关,随着酸价的升高,1～42日龄肉鸡平均采食量和42日龄体重逐渐降低,其中劣质混合油C组采食量显著降低。     

Effects of high ambient temperature on plasma metabolomic profiles in chicks

Exposure to high ambient temperature is detrimental to the poultry industry. To understand the influence from a metabolic perspective, we investigated the effects of exposure to high ambient temperature on plasma low‐molecular‐weight metabolite levels in chicks using gas chromatography/mass spectrometry‐based non‐targeted metabolomic analysis. Heat exposure for 4 days suppressed growth and food intake. Of the 92 metabolites identified, the levels of 29 decreased, whereas the levels of nine increased. We performed an enrichment analysis on the identified metabolites and found 35 candidates for metabolic processes affected by heat exposure. Among them, the sulfur amino acid metabolic pathway was clearly detected and the levels of the following related metabolites were decreased: cystathionine, cysteine, cystine, homocysteine and hypotaurine. Changes in the kynurenine pathway in tryptophan metabolism, which is linked to the immune system and oxidative stress, were also observed: kynurenine and quinolinic acid levels increased, whereas nicotinamide levels decreased. These results suggest the possible involvement of various metabolic processes in heat‐exposed chicks. Some of these metabolites would be important to understand the mechanism of biological responses to high ambient temperature in chicks.     

Inhibition of adrenal steroidogenesis,food restriction and acclimation to high ambient temperatures in chickens

1. White Plymouth Rock chickens placed under 60% food restriction or ad libitum feeding, with or without metyrapone treatment, from either 4 to 6 (early) or 24 to 26 (late) d of age were exposed to high ambient temperatures (35 ± 2°C) from 36 to 43 d of age.

2. Stress attributable to fasting was not manifested through leucocytic alteration when food‐restricted chicks were supplemented with an adrenal blocking chemical, metyrapone.

3. Provision of metyrapone during the fasting period resulted in inferior compensatory growth during refeeding.

4. Exposure to high temperatures from 36 to 43 d of age did not cause an elevation in the heterophihlymphocyte (H/L) ratios of chicks that had eaten metyrapone‐treated food ad libitum during the neonatal stage.

5. During heat exposure, chicks that had been subjected to early 60% restriction with non‐metyrapone‐treated food had lower H/L ratios and improved resistance to marble spleen disease infection.     

Response of broiler chickens reared at high density to dietary supplementation with licorice extract and probiotic

This study evaluated the effects of licorice extract and probiotic on performance, excreta characteristics and welfare‐related parameters of broiler chickens reared in high stocking density. Three hundred and thirty‐six 1‐day old broiler chicks (Ross 308) were used in a completely randomized design with five treatments and four replicates for 42 days. Treatments were as follows: (a) positive control (PC, 12 chicks/m²); (b) negative control (NC, 18 chicks/m²); (c) NC + 500 ppm licorice extract (LE); (d) NC + 200 ppm probiotic (P); (e) NC + ppm LE + ppm P. Body weight gain (BWG) was affected negatively by increased density in the growing period (p < 0.05). At high density, BWG was increased in the growing and whole period by adding LE and P separately and in combination (p < 0.01). Feed conversion ratio (FCR) was not affected by stocking density. Excreta weight (g/bird) and dry matter (DM, %) were reduced by increasing density (p < 0.01). Use of feed additives at high stocking density had no significant effect on excreta weight, but DM content of excreta was higher in NC + LE + P than NC. Gait problems and footpad and hock burns were increased by increased stocking density, but were not altered by feed additives. In conclusion, licorice extract and probiotic improved BWG of broilers reared at high stocking density; however, these birds had some disorders in footpad, hock and walking ability.