Effect of an organic acid blend and phytase added to a rapeseed cake‐containing diet on performance,intestinal morphology,caecal microflora activity and thyroid status of broiler chickens

The experiment was carried out on 96 female broilers, allocated to eight groups of 12 birds kept in individual cages. Two basal wheat‐ and soyabean meal‐based diets containing 150 g/kg of rapeseed expeller cake were formulated, differing in the level of P: 7.1 g/kg in diet H or 5.9 g/kg in diet L. Rapeseed cake supplied 3.15 μmol alkenyl glucosinolates per gram of diet. The eight treatments were: basal diets only, basal diets + phytase (1000 U/kg), basal diets + organic acid blend (OA, 6 g/kg), or basal diets + both additives. Diets were fed from day 8 to 28 of life. The results showed that the lower dietary P content and OA supplementation did not significantly affect feed intake or BWG, while both increased (p < 0.001) after phytase supplementation. Tibia ash content as well as tibia ultimate strength were lower (p < 0.001) in birds fed diets L compared with diets H, and increased (p < 0.01) with phytase supplementation of diet L, while OA had no influence on either parameter. Dietary P levels and OA supplementation had no influence on the pH of gut digesta, but the pH of jejunal digesta increased following phytase supplementation (p < 0.01). Morphological measurements of the small intestinal mucosa of chicks indicated that OA added to diet L depressed villi height (p < 0.001) and crypt depth (p < 0.001); both parameters increased after phytase supplementation (p < 0.01). The lower total SCFA as well as acetic, propionic and butyric acid concentrations in caecal digesta indicated lower activity of caecal microflora in birds fed diets L compared with H. OA supplementation had no influence, while phytase supplementation increased the concentration of acetic acid in caecal digesta. Supplementation of diets with either phytase or OA increased thyroid weight by 16% (p < 0.01) and 11% (p < 0.05) respectively. The increase in thyroid weight because of phytase supplementation was greater at the lower dietary P level, and the greatest when both phytase and OA were added to the diet.     

Investigation into selenium requirement of growing turkeys offered a diet supplemented with two levels of vitamin E

To evaluate dietary selenium (Se) requirement in turkeys offered a diet supplemented with two levels of vitamin E (VE), 96 newly hatched male BIG 6^® chicks (58.4 ± 4.12 g) were divided into eight groups of 12 animals each and fed maize soya diets containing 0.05, 0.10, 0.20 and 0.30 mg Se/kg from sodium selenate in combination either with the natural VE content (approximately 10 IU/kg) or with a VE addition of 50 IU/kg. Animals from all the groups were highly performant and their final body weights (1746 ± 190 g) after 35 days on experiment were not significantly different. According to its dietary supply, Se concentration in the liver and plasma increased dose dependently. Independent of dietary VE, the activities of GPx3 in plasma and of GPx1 in liver and breast muscle increased to a larger extent in turkeys supplemented with 0.10 and 0.20 mg Se/kg in relation to animals with low marginal Se supply (0.05 mg/kg). Supplementation of 0.30 mg Se/kg only slightly increased further selenoprotein activities. 2‐Thiobarbituric acid reactive substances in the liver were strongly reduced by dietary VE, but not by Se. Plasma aspartate aminotransferase (AST) and creatine kinase (CK) activities did not show muscular lesions in none of the groups. Although there were no signs of muscular lesions even in turkeys with marginal Se and moderate VE supply, the activity of selenoproteins in various organs increased up to 0.30 mg Se/kg diet, independent of VE supply. It was concluded that for growing turkeys the Se supply should meet at least a level of 0.20 mg/kg diet as currently recommended by the National Research Council and Gesellschaft für Ernährungsphysiologie. Vitamin E addition confirmed the particular function of the vitamin as a lipid antioxidant and should be taken into consideration when diets with high PUFA concentrations are fed.     

Effect of excess dietary sodium, potassium, calcium and phosphorus on excreta moisture of laying hens

1. Four experiments were conducted to investigate the effects of dietary concentrations of sodium, potassium, calcium or phosphate on the water intake and excreta moisture of laying hens. A fifth experiment examined the effect on these variables of increasing amounts of 2 different sodium salts (chloride or bicarbonate) and the interactions with 2 levels of dietary phosphorus. 2. All experiments involved individually caged laying hens fed on diets varying in 1 or 2 minerals in replacement for washed sand. The experimental diets contained mineral concentrations that either met or exceeded the expected requirement of the hens. The diets were given for a 7 or 8 d feeding period and food and water intakes were measured and excreta were collected for the last 48 h of each feeding period. These data were corrected for evaporative water loss to the environment during the collection period. 3. Increasing dietary concentrations of sodium, potassium or phosphorus gave linear increases (P<0.001) in the water intake of the laying hens and linear increases (P<0.01) in the moisture content of their excreta. Each 1 g/kg increase in dietary mineral increased the moisture content of the excreta by 9.04 (+/- 1.57), 11.95 (+/- 2.02) and 5.59 (+/- 0.31) g/kg (+/- standard error) for sodium, potassium and phosphorus, respectively. Increasing concentrations of dietary calcium did not significantly affect the water intakes or excreta moisture levels of the laying hens. 4. The fifth experiment showed that, although there was a sodium x phosphorus interaction (P<0.05), the effects of the 2 mineral additions were approximately additive. There were no significant differences (P>0.05) in water intakes or excreta moisture contents due to the 2 different sodium salts (chloride or bicarbonate).     

Dietary phytate (inositol hexaphosphate) regulates the activity of intestinal mucosa phytase

The role of dietary phytate (inositol hexaphosphate) in the regulation of intestinal mucosa phytase was investigated in chicks. Seven-day-old chicks were grouped by weight into six blocks of three cages with six birds per cage. Three purified diets [a chemically defined casein diet, a chemically defined casein diet plus sodium phytate (20 g/kg diet) and a chemically defined casein diet plus sodium phytate (20 g/kg diet) and microbial phytase (1000 units/kg diet)] were randomly assigned to cages within each block. Chicks were fed experimental diets from 8 to 22 days of age then killed, and duodenal mucosa and left tibia removed. Phytase activity in duodenal mucosa, growth performance and bone ash content were determined. Addition of phytate to the chemically defined casein diet reduced (p < 0.05) the V(max) of the duodenal brush border phytase, but the K(m) of the enzyme was not affected. Addition of phytate also reduced (p < 0.05) weight gain, feed intake, feed efficiency and percentage ash. Addition of microbial phytase fully restored the feed efficiency (p < 0.05), but V(max) and body weight gain were only partially restored (p < 0.05). In conclusion, it would seem that dietary phytates non-competitively inhibit intestinal mucosa phytase.     

Effects of dietary calcium and phosphorus on mineral retention,growth, feed efficiency and walking ability in growing turkeys

1. Large White male turkeys from a heavy commercial male-line were fed on 16 diets containing 4 concentrations of calcium (6, 10, 14 and 18 g/kg) and available phosphorus (3, 5, 7, 9 g/kg) in a 4 x 4 factorial experiment with three replicates (pens). Turkeys were weighed and food intakes recorded from 4 to 7, 8 to 10 and 11 to 13 weeks of age. 2. The diets containing 6 g/kg calcium and 5, 7 or 9 g/kg available phosphorus concentrations were associated with lower body weighs at 10 and 13 weeks of age. 3. Fewer than 6% of the turkeys had an abnormal gait at 13 weeks of age. 4. The optimum dietary concentrations were 10 g/kg of calcium and 3 g/kg of available phosphorus. It was concluded that these concentrations should be fed at least to 13 weeks of age. 5. Retentions of dietary calcium and phosphorus averaged 300 g/kg of intake. 6. Utilisation of dietary phytate ranged from 5 to 11 g/kg and it is recommended that organic phosphorus should be ignored in the formulation of diets for growing turkeys unless they are supplemented with a phytase enzyme.     

High-fiber diets in pregnant sows: digestive utilization and effects on the behavior of the animals

Twelve pregnant, multiparous sows were assigned during gestation to three dietary treatments in a 3 x 3 Latin square design to evaluate the effect of increasing levels of crude fiber (CF): a conventional diet low in CF (L, 15.8 MJ DE/kg of DM, 3.3% CF), a diet with a medium level of CF (M, 14.4 MJ DE/kg of DM, 10.6% CF), and a high-fiber diet (H, 12.9 MJ DE/kg of DM, 18.1% CF). The daily feed supply was adjusted to provide the same 33.4 MJ of daily digestible energy (2.4, 2.7, and 3.0 kg/d for diets L, M, and H, respectively). Over the day, a shorter time standing was spent when sows received the H diet (291 min/d) compared with the L (363 min/d) and M diets (324 min/d). Duration of feeding was longer with the high-fiber diet. Mastication represented the main part of the feeding activity in sows fed the H diet (56%) and was reduced with the M and L diets (40% and 25%, respectively). Feeding rate increased when fiber level decreased (67, 120, and 152 g/min for the H, M, and L diets, respectively). Feeding the fibrous diet reduced the incidence of nonfeeding oral behaviors. These results show that high-fiber diets can reduce apparent feeding motivation of pregnant sows and, thus, improve the welfare of sows subjected to feed restriction.     

Chronic effects of moniliformin in broiler and turkeys fed dietary treatments to market age

Floor pen studies were conducted, with broilers from 1 to 7 wk of age and with turkeys from 1 to 14 wk of age, to evaluate the chronic effects of moniliformin (M). Fusarium fujikuroi (M-1214) culture material was added to typical corn-soybean basal diets to supply 0, 25, or 50 mg M/kg diet (broilers) or 0, 12.5, 25, 37.5, or 50 mg M/kg diet (turkeys). Compared with controls, chicks fed diets containing 50 mg M/kg consumed more feed, had lower body weight gain, were less efficient in converting feed to body weight gain, and had increased relative heart and proventriculus weights. Chicks fed the diet containing 50 mg M/kg also had significantly higher mortality and decreased mean corpuscular volumes compared with controls. Broilers fed 25 and 50 mg M/kg also had increased serum gamma glutamyltransferase activities. Feed intake, body weight gain, and feed conversion of turkeys fed dietary M were not affected. At 6 and 14 wk, turkeys fed 25, 37.5, or 50 mg M/kg diet had increased (P < 0.05) relative heart weights when compared with controls. At week 14, turkeys fed diets containing 37.5 or 50 mg M/kg also had increased (P < 0.05) relative liver weights compared with turkeys fed 0, 12.5, or 25 mg M/kg diet. Lesions, observed only in the hearts of broilers and turkeys fed 50 mg M/kg, were loss of cardiomyocyte cross striations, increased cardiomyocyte nuclear size, and an increased number of cardiomyocyte mitotic figures (turkeys only). Results indicate that > or = 37.5 mg M/kg is hepatoxic and > or = 25 mg M/kg is cardiotoxic to turkeys and 50 mg M/kg diet is toxic to broilers fed to market age.     

Effect of dietary dried oregano leaves on growth performance, carcase characteristics and serum cholesterol of female early maturing turkeys

1. A study was conducted with 120 female early maturing turkeys to test the effect of dietary dried oregano leaves (Origanum vulgare subsp. hirtum) on body weight (BW), feed intake (FI), feed conversion efficiency (FCE), carcase characteristics and serum cholesterol concentration. Dried oregano leaves had a content of 3.6 ml essential oils/100 g, while the carvacrol content was 855 g/kg of the total essential oils. 2. From 1 to 84 d of age, the turkeys were fed on 4 diets varying in oregano content (OR0, no oregano--control; OR45, 1.25 g oregano/kg; OR90, 2.5 g oregano/kg; OR135, 3.75 g oregano/kg). Birds were given feed and water ad libitum. 3. BW was unaffected by oregano throughout the experiment. FI and FCE were similar among all treatments until 42 d of age. From 43 to 84 d of age and for the overall experimental period, FI decreased linearly in treatment OR135 and FCE increased linearly with dietary oregano content. Body and carcase weights, carcase yield, and the relative weights of the heart and liver were not significantly affected by oregano content. The relative weights of the gizzard and small intestine decreased linearly with oregano content. Serum cholesterol content was similar among all treatments. 4. In the present study, dietary oregano (1.25, 2.5 and 3.75 g/kg) improved FCE in female early maturing turkeys between 43 and 84 d, with the lowest oregano inclusion (1.25 g/kg) giving the most cost effective diet. Thus, dried oregano leaves may be used as a natural herbal growth promoter for early maturing turkeys.     

Effects of an experimental phytase on performance, egg quality, tibia ash content and phosphorus bioavailability in laying hens fed on maize- or barley-based diets

A 24-week performance trial was conducted to evaluate the efficacy of an experimental phytase on performance, egg quality, tibia ash content and phosphorus excretion in laying hens fed on either a maize- or a barley-based diet. At the end of the trial, an ileal absorption assay was conducted in order to determine the influence of phytase supplementation on the apparent absorption of calcium and total phosphorus (P). Each experimental diet was formulated either as a positive control containing 3.2 g/kg non-phytate phosphorus (NPP), with the addition of dicalcium phosphate (DCP), or as a low P one, without DCP addition. Both low P diets (containing 1.3 or 1.1 g/kg NPP) were supplemented with microbial phytase at 0, 150, 300 and 450 U/kg. The birds were housed in cages, allocating two hens per cage as the experimental unit. Each of 10 dietary treatments was assigned to 16 replicates. Low dietary NPP (below 1.3 g/kg) was not able to support optimum performance of hens during the laying cycle (from 22 to 46 weeks of age), either in maize or barley diets. Rate of lay, daily egg mass output, feed consumption, tibia ash percentage and weight gain were reduced in hens fed low NPP diets. The adverse effects of a low P diet were more severe in hens on a maize diet than in those on a barley diet. Low dietary NPP reduced egg production, weight gain, feed consumption and tibia ash content and microbial phytase supplementation improved these parameters. Hens given low NPP diets supplemented with phytase performed as well as the hens on positive control diets containing 3.2 g/kg of NPP. A 49% reduction of excreta P content was achieved by feeding hens on low NPP diets supplemented with phytase, without compromising performance. Phytase addition to low NPP diets increased total phosphorus absorption at the ileal level, from 0.25 to 0.51 in the maize diet and from 0.34 to 0.58 in the barley diet. Phosphorus absorption increased linearly with increasing levels of dietary phytase. Mean phosphorus absorption was higher in barley diets than in maize diets (0.49 vs 0.39).     

Effects of dietary metabolisable energy, calcium and phosphorus on bone mineralisation, leg weakness and performance of broiler chickens

1. Performance, gait score (GS), tibial dyschondroplasia (TD), and tibia bone mineralisation and breaking strength were determined in 2880 male and female Ross 208 broilers fed on diets with two different concentrations of dietary metabolisable energy (ME) (11.00 or 12.00 MJ/kg) and 4 different concentrations of available phosphorus (aP) adjusted for dietary ME content (4.0, 4.5, 5.0 or 5.5 g/kg aP in starter and 3.5, 4.0, 4.5 or 5.0 g/kg aP in finisher diets containing 12.00 MJ/kg). 2. Tibia ash, calcium (Ca) and phosphorus (P) contents in broilers given diets with low ME (11.00 MJ/kg) were greater than those of broilers given diets with higher ME (12.00 MJ/kg). Tibia ash, Ca and P contents increased curvilinearly with increasing dietary aP content. The dietary aP level had no effect on GS. 3. Dietary concentration of ME or aP had no effect on tibia breaking strength. 4. Walking ability, as measured by GS, was negatively correlated with the body weight (BW) of tested birds at 23 and 35 d of age, but the dietary ME content or aP level had no significant effect on GS at 35 d of age. 5. The results indicated that bone mineral content had no clear correlation with the walking ability of broilers.     

The influence of different lipid sources and levels on growth, body composition and haematology of Huso huso

In order to improve feeding and growth of juvenile great sturgeon Huso huso, the effects of various lipid sources in feed were examined. Three hundred juveniles (initial body weight 215 ± 10 g) were distributed into 15 flow-through 1100 l tanks (20 fish per tank). Five experimental diets containing various lipid levels were formulated: diet C (control; without added oil), SO(L) and SO(H) diets containing soybean oil concentrations respectively, (53.5 vs. 174 g/kg), FO(L) and FO(H) diets containing fish oil with low and high concentrations respectively (53.5 vs. 174 g/kg). Fish were fed three times daily based on their appetite for a period of 6 weeks. At the termination of the experiment, growth rate was improved with increasing oil content in the diets. There were significant differences in final weights among fish fed the different experimental diets. Lipid content of muscle and liver significantly increased with increasing dietary lipid levels for both soybean and fish oil. The lowest cholesterol level and the highest haematocrit value were measured in fish fed the FO(H) diet. No significant difference was found among dietary treatments in terms of triacylglycerol concentration, number of red blood cell, mean corpuscular volume, mean corpuscular haemoglobin (MCH) and MCH concentration (MCHC). According to the most growth indices, results of this study suggest that the best results were observed in FO(H) which can be attributed to the greater palatability of diet containing high fish oil, supply of fatty acid requirement and enhanced physiological performance.     

Blood proteins and amino acids of female breeder turkeys fed on maize-soybean diets supplemented with methionine

Two hundred and six female breeder turkeys were fed on maize-soybean diets of equal energy content, containing 100, 120 or 140 g crude protein (CP)/kg to which DL-methionine was added at 0, 1, 2 or 3 g/kg diet in a factorial design. Serum albumin concentrations were found to be more sensitive measures of dietary protein adequacy than were total serum protein concentrations. Albumin concentrations at peak egg production were highest among birds fed on 120 and 140 g CP/kg diets. Four weeks later, they were highest only for those on the 140 g CP/kg diet. The elevated concentrations of blood threonine and lysine and the decreased concentration of glycine with increased dietary protein were in agreement with the data on egg production. These data suggested that a sub-optimal balance of dietary amino acids may have occurred.     

Effect of dietary cation-anion balance in mineral balance in anaerobically exercised and sedentary horses

Eight geldings and four mares were randomly assigned treatments within three 4x4 Latin square design experiments to study the effects of dietary cation-anion balance (DCAB) on mineral balance and dry matter digestibility in sedentary and anaerobically exercised horses. Four diets with an average DCAB (calculated as meq ((Na+K+) - Cl-)/kg of diet dry matter) of +24 (Low, L), +127 (Medium Low, ML), +227 (Medium High, MH) and +352 (High, H) were fed for a 21 day adjustment period followed by a 72 hour collection period. Diets consisted of a pelleted base concentrate of com, soybean meal and cottonseed hulls fed with either native prairie grass or bermuda grass hay in a 60:40 ratio. Diet L was formed by adding calcium chloride and ammonium chloride to the base concentrate, diet ML was formed by adding calcium chloride, and diet H was formed by adding potassium citrate and sodium bicarbonate. Diet MI-I received no supplementation and served as the control. Representative samples of feed, feces and urine were analyzed for mineral content and mineral balances were calculated by difference. Fecal output was greater (p <.05), and thus, dry matter digestibility was lower in exercised homes consuming diet L versus diet H. Sodium balance was greater (p <.05) in sedentary horses consuming diet MH as compared to those consuming diets ML and L Sodium balance was greater (p <.05) in exercised homes consuming diet H as compared to those consuming diets ML and L Potassium balance was greater (p <.05) in sedentary horses consuming diet H as compared to those horses consuming diet ML, however, potassium balance was not affected by DCAB in exercised horses. No significant differences were detected in chloride or magnesium balances in the sedentary horses, although chloride balance was greater (p <.05) and magnesium balance was lower (p <.05) in exercised homes consuming diet L as compared to all other diets. In sedentary homes, phosphorus balance was reflective of intake with differences (p <.05) observed between all treatments. However, in exercised homes, phosphorus balance was lower (p <.05) oniy for those consuming diet L. Calcium balance decreased significantly as DCAB decreased between all treatments in sedentary horses, while calcium balance in exercised homes was greater (p <.05) for homes consuming diet H as compared to those consum- ing diet L.Previous research from our laboratory has shown that both exercised and sedentary horses consuming diets with a low DCAB experience a nutritionally induced metabolic acidosis. The current data indicate that anaerobically exercised and sedentary horses consuming these diets excrete significantly more calcium in the urine resulting in decreased calcium balances. Prolonged consumption of diets with a low DCAB may lead to a significant demineralization of bone and a subsequent weakening of the skeleton.     

Response of Laying Hens and Growing Broilers to the Dietary Inclusion of Mango (Mangifera indica L.) Seed Kernel Meal

Studies were carried out to assess the nutritive value and utilization of mango (Mangifera indica L.) seed kernel (MSK) in the diets of layer and broiler chickens. The physical component of mango seeds was found to consist of 678 g/kg kernel, 292 g/kg shell and 30 g/kg testa. Meal from the seed kernel contained 61.6 g crude protein, 136.2 g ether extract, 22.3 g ash, 46.4 g crude fibre, 673.5 g nitrogen-free extract and appreciable mineral content. In the layers trial, MSK replaced maize weight for weight at 0, 50, 100, 150, 200 and 250 g/kg. Results indicated a significant decrease (p < 0.05) in feed intake, rate of lay, egg mass and feed efficiency with increase in MSK. Layers on 150, 200 and 250 g/kg MSK exhibited the highest body weight losses. Except for lower shell thickness (p < 0.05) in hens fed MSK at 200 and 250 g/kg, the internal egg quality characteristics were comparable. In the broiler experiment, MSK was incorporated at levels of 0, 50, 100, 150 and 200 g/kg at the expense of maize but with slight adjustments to the soybean meal so as to achieve isonitrogenous diets. Body weight and body weight gains increased significantly (p <0.05) up to 100 g/kg and then decreased. MSK at 150 or 200 g/kg had no significant effects (p >0.05) on feed intake and feed efficiency when compared with control diet. Organ weights with the exception of liver and lung were unaffected by dietary MSK. Haematological indices were not influenced (p > 0.05) by dietary MSK except haemoglobin and mean cell haemoglobin, which were higher (p<0.05) in broilers fed 100 g/kg MSK. Neutrophils, lymphocytes and albumin/ globulin ratio were similar on all diets. The results indicated that at higher weight for weight levels, MSK cannot readily substitute maize in layer diets, whereas a marginal improvement was recorded in the broiler diet, albeit with nutrient supplementation.     

Which source and level of dietary sodium is appropriate for broiler chickens reared in a high‐altitude area?

This study investigated effect of increasing level of dietary sodium using sodium bicarbonate or sodium chloride on growth performance, mortality, characteristics of carcass, organs and tibia, calcium and phosphorus of serum in broilers reared in a high‐altitude area (1,700 m above sea level). A total of 588 Ross 308 male broiler chicks were used in seven treatments, six replicates per treatment of 14 birds per each from 1 to 38 d of age. Seven dietary treatments consisted of a basal diet (with 0.16% sodium and 0.23% chloride), top‐dressed for six diets to give three supplementary levels of sodium (0.07%, 0.14% and 0.21%) from sodium bicarbonate (respectively by 0.26%, 0.52% and 0.78%) or sodium chloride (respectively by 0.18%, 0.36% and 0.54%), resulting in seven diets with total sodium and chloride levels of 0.16% and 0.23%, 0.23% and 0.23%, 0.30% and 0.23%, 0.37% and 0.23%, 0.23% and 0.33%, 0.30% and 0.44%, 0.37% and 0.55% respectively. Increasing sodium level improved feed conversion ratio (FCR) linearly and quadratically. However, when FCR was calculated without adjusting for feed intake of mortalities, the enhanced sodium level did not improve this parameter. Increasing sodium level via sodium chloride enhanced ascites mortality, total mortality, relative weight of heart and right ventricle linearly. Increasing sodium level reduced serum calcium and enhanced serum phosphorus linearly; however, there was a linear tendency to increase tibia ash when sodium level was enhanced by sodium bicarbonate (p = 0.08) or sodium chloride (p = 0.07). Increasing sodium level via sodium bicarbonate tended (p = 0.08) to reduce tibia strength linearly. In conclusion, a diet with 0.16% sodium and 0.23% chloride is enough for broiler chicken reared in a high‐altitude area, and increasing dietary sodium level via sodium chloride has detrimental effect on survivability of broiler in such condition.     

饲粮添加不同水平维生素D_3对肉仔鸡生长性能和骨磷代谢利用的影响

本试验旨在研究饲粮中添加不同水平维生素D3(VD3)对肉仔鸡生长性能及骨磷代谢利用的影响。试验选用480只1日龄艾拔益加肉公雏,采用2×4双因子完全随机设计,设2个饲粮非植酸磷水平[0.45%和0.23%(实测值为0.44%和0.21%)]与4个VD3添加水平(0、1 000、2 000和4 000IU/kg),共8个组,每组6个重复,每个重复10只鸡。试验期21d。结果表明,与0.21%非植酸磷水平相比,0.44%非植酸磷水平显著提高肉仔鸡平均日增重(ADG)、平均日采食量(ADFI)、胫骨灰分含量和胫骨灰分磷含量(P0.05),显著降低料重比(F/G)和胫骨灰分磷绝对沉积率(P0.05);与不添加VD3相比,饲粮中添加VD3显著提高肉仔鸡ADG、15~21和1~21日龄ADFI、胫骨灰分含量和胫骨灰分磷绝对沉积率(P0.05),显著降低1~21日龄肉仔鸡F/G(P0.05);0.21%非植酸磷水平下,与不添加VD3相比,饲粮中添加VD3显著降低肉仔鸡死亡率(P0.05),显著提高21日龄肉仔鸡胫骨灰分磷重量(P0.05),添加2000IU/kg VD3显著提高14日龄肉仔鸡胫骨灰分磷重量(P0.05);0.44%非植酸磷水平下,与不添加VD3相比,饲粮中添加VD3显著提高肉仔鸡胫骨灰分磷重量(P0.05)。以上结果表明,饲粮中添加VD3可提高肉仔鸡的生长性能并降低死亡率,促进磷在骨骼中的代谢利用。     

Effect of dietary cation-anion balance on urinary mineral excretion in exercised horses

Four mares and four geldings of Quarter Horse and Thoroughbred breeding were used in two simultaneous 4x4 Latin square experiments to study the effects of dietary cation-anion balance (DCAB), defined as meq ((Na+K)-C1)/kg dry matter, on urinary pH and mineral excretion in exercised horses. Diets consisted of a pelleted concentrate of corn, soybean meal and cottonseed hulls fed with bermudagrass hay. Treatments with DCAB of +5 (Low, L), +107 (Medium Low, ML), +201 (Medium High, MH) and +327 (High, H), meq ((Na+K)-Cl)/kg dry matter were formed by supplementing diet L with calcium chloride and ammonium chloride, diet ML with calcium chloride and diet H with sodium bicarbonate and potassium citrate (Table 1). Diet MH was not supplemented and served as the control treatment. Horses were conditioned aerobically for 6 weeks using long, slow, distance (LSD) workouts. During the experimental periods, horses were subjected to a combined exercise regimen alternating LSD with an interval-training protocol 6 days/week. There was a significant (P<.01) treatment effect on urine pH; least squares means for L, ML, MH and H were 6.73, 7.17, 7.38, and 7.92. Horses consuming diet L excreted more calcium in the urine (P<.05) than those consuming MH or H. Least squares means for daily urine calcium excretion tended to be linear across treatments and ranged from 19.66 g/day for diet L to 9.12 g/day for diet H. Urinary chloride excretion was higher (P<.05) for L than for MH or H. Horses fed diet H excreted more sodium (P<.05) in urine than horses fed the other diets. Lowering DCAB, increases urinary calcium loss; depending on the level of calcium intake, this could lead to negative calcium balance in exercising horses.     

Effects of sex and protein and energy levels in the diet on the blood parameters of the chukar partridge (Alectoris chukar)

1. The effects of sex and dietary composition were investigated in 48 male and 48 female 16-week old chukar partridges. 2. Sixteen starter and 16 grower diets were arranged in a 4 x 4 factorial design with 4 concentration of crude protein (CP) and 4 concentration of metabolizable energy (ME). 3. Blood samples were collected at 16 weeks of age and analysed for total protein, triglycerides, uric acid, total cholesterol, glucose, calcium, phosphorus, sodium, potassium and chlorine. 4. There were no significant effects of sex on the measured parameters. 5. Serum total protein was highest in partridges fed on a diet containing 200/175 g CP/kg (starter grower). Serum cholesterol concentrations of partridge fed the diet with 240/200 or 280/225 g CP/kg were significantly higher than that for partridge fed diets containing a lower gCP/kg. 6. Serum total protein and glucose levels significantly decreased as dietary energy level was increased. Serum triglycerides and calcium were highest in partridge fed on the diets containing 13.39/13.81 and 11.71/12.55 ME MJ/kg, respectively. Serum phosphorus and chloride levels were highest in partridges given the diet containing 10.88/11.92 ME MJ/kg. 7. There were significant interactions between the effects of CP and ME on serum triglycerides, sodium and potassium levels. 8 The results of this study suggested that dietary CP, and especially ME concentration, significantly affect blood parameters in chukar partridge.     

Effects of two Neepawa wheats (triticum aestivum,l.) fed at two protein concentrations with added dietary lysine on growth of turkey poults

1. Two Neepawa wheats (145 and 210 g protein/kg) were tested in diets of two protein contents (220 and 280 g protein/kg) with or without added dietary lysine (0, 1, 2, 3, 4 or 5 g/kg) in a factorial experiment with young male turkeys (1 to 28 d). The protein contents of the diets were obtained by varying the proportions of the wheats and soyabean meal.

2. Irrespective of the Neepawa wheat used or lysine added, maximum growth was not obtained with diets containing 220 g protein/kg.

3. There was no response to lysine added to diets of 280 g protein/kg containing the 145 g protein/kg Neepawa wheat, but there was such a response in such diets containing the 210 g protein/kg wheat.

4. It is concluded that the Neepawa wheat containing 210 g protein/ kg, when supplemented with lysine, can replace soyabean meal in diets for young turkey poults.     

Fatty acid requirements of breeding turkeys

1. Turkey hens were fed during the breeding period on 5 diets containing different amounts of linoleic acid and total fat provided by varying supplements of maize or olive oils. 2. Reproductive performance of the turkeys increased in response to dietary linoleic acid. Eleven g linoleic acid/kg diet gave optimum poult production. 3. Egg weight did not show a significant response to dietary fat content. 4. Adipose tissue fatty acid composition of the hens was influenced by dietary oleic and linoleic acid content.