Evaluation of optimal dietary calcium level by bone characteristics and calcium metabolism-related gene expression of broilers from 22 to 42 d of age

The current dietary Ca recommendation of broilers is primarily based on the previous studies carried out more than 30 yr ago. However, the modern commercial broilers are quite different from those more than 30 yr ago. The present experiment was conducted to evaluate an optimal dietary Ca level by bone characteristics and Ca metabolism-related gene expression of broilers fed a corn-soybean meal diet from 22 to 42 d of age. A total of 252 22-d-old Arbor Acres male broilers were randomly assigned to 1 of 7 treatments with 6 replicate cages of 6 birds per cage for each treatment. Broilers were fed the corn-soybean meal diets containing 0.50%, 0.60%, 0.70%, 0.80%, 0.90%, 1.00%, or 1.10% Ca for 21 d, and each diet contained 0.31% non-phytate P. The results showed that the mineral contents in tibia and middle toe bone, mineral density in tibia and middle toe bone, middle toe ash percentage, middle toe ash Ca percentage, and tibia alkaline phosphatase mRNA expression level of broilers were influenced (P < 0.04) by dietary Ca level and increased quadratically (P < 0.05) as dietary Ca level increased. The estimates of optimal dietary Ca levels were 0.55%, 0.60%, 0.70%, 0.72%, 0.63%, 0.66%, and 0.70%, respectively, based on the best fitted broken-line, quadratic, or asymptotic models (P < 0.02) of the above sensitive indices. These results indicate that the optimal dietary Ca level would be 0.72% to support all of the Ca metabolism and bone development of broilers fed the corn-soybean meal diet from 22 to 42 d of age.

A Novel Corn-Expressed Phytase Improves Daily Weight Gain, Protein Efficiency Ratio and Nutrients Digestibility and Alters Fecal Microbiota in Pigs Fed with Very Low Protein Diets

The objective of this study was to assess the effect of a novel corn-expressed phytase (CEP) on growth, nutrients digestibility, bone characteristics and fecal microbiota of pigs fed with very low-protein, -calcium (Ca) and -phosphorous (P) diets. Forty-eight barrows were subjected to 6 groups for 4 weeks: positive control-adequate protein (PC), negative control-reduced protein (NC), NC + low-dose CEP, i.e., 2000 FTU/kg (LD), NC + high-dose CEP, i.e., 4000 FTU/kg (HD), LD with 0.12% unit reduced Ca and 0.15% unit reduced available P (LDR), and HD with 0.12% unit reduced Ca and 0.15% unit reduced available P (HDR). Compared to NC, LD and HDR had a higher average daily gain (ADG) and gain:protein ratio (G:P), HD and HDR had greater apparent fecal digestibility of Ca and P and bone mineral density and LDR and HDR had lower serum osteocalcin. The feces of LD was enriched in Lachnospiraceae, while the HD had a higher abundance of Succinvibrio and LDR had a higher abundance of Bifidobacterium and Actinobacteria. In conclusion, supplementation of protein-restricted diets with a CEP decreased their negative effects on ADG and G:P ratio, increased the digestibility of Ca and P regardless of the levels of these minerals in the diet, improved bone characteristics and produced differential effects on fecal bacterial population.

Vitamin D3 enhanced intestinal phosphate cotransporter genes in young and growing broilers

The influence of dietary vitamin D₃ (VD3) levels on growth, bone performance, and duodenal type IIb sodium-dependent phosphate cotransporter (NaPi-IIb) genes in broiler chicken were studied. One-day-old male Ross308 broilers (n = 432) were allocated into 6 treatment groups with each group consisting of 6 cage pens. Each treatment group received diet containing different amounts of VD3 (80, 200, 500, 1,250, 3,125, or 7,813 IU per kg of diet) from a day-old to 31 D of age. Dietary available phosphorus and calcium were kept the same across all treatments in each phase. At 14 D, influence of VD3 on BW gain was found in the birds that received VD3 of 3,125 IU/kg and 200 IU/kg (P < 0.05). Toe ash and tibia ash linearly increased (P < 0.05) at 14 D with increase in dietary VD3_. There was no significant influence of dietary VD3 on tibia breaking strength. In both phases, relative expression of duodenal NaPi-IIb linearly increased (P < 0.01) with increase in dietary VD3. At 14 D, highest expression of 3.2 folds was observed in birds treated with VD3 at 7,813 IU/kg of feed. At 31 D, birds that received VD3 levels of 3,125 and 7,813 IU/kg of feed showed 2.9 folds higher in NaPi-IIb expression compared with those fed lowest level of VD3 at 80 IU/kg of feed. When dietary calcium and phosphorus were maintained at the standard requirement, increase in dietary VD3 did not improve growth performance. For optimum growth and bone characteristics, dietary inclusion of VD3 at 500 IU/kg was adequate for both starter and grower broiler diets. Vitamin D₃ enhanced the expression of NaPi-IIb at higher doses and thus improving the tibia ash content in high VD3 treatment groups. This study reported for the first time an increased in the expression of duodenal NaPi-IIb in 31-day-old broilers in response to high dietary VD3 levels.

Influence of bone meal degelatinisation and calcium source and particle size on broiler performance, bone characteristics and digestive and plasma alkaline phosphatase activity

1. The current experiment was performed to elucidate the effects of degelatinised bone meal (DBM) in combination with different particle sizes of limestone or oyster shell on broiler performance, bone characteristics and digestive and plasma alkaline phosphatase (ALP) activity. 2. Treatments were applied as a 3 × 3 factorial arrangement with three sources of P (DCP, bone meal and DBM) and three particle sizes (50, 100 and 200 µm) of limestone. Chickens were given either DCP or DBM with oyster shell (523 µm), resulting in a total of 11 treatments with 5 replicates of 8 chicks. 3. Performance criteria were measured weekly. Tibia strength, ash, calcium (Ca) and phosphorus (P) content and plasma P and Ca concentration along with plasma and intestinal alkaline phosphatase (ALP) activity and P digestibility were measured on d 14 and 28. 4. Body weight and FCR were improved in chicks which were fed DBM or oyster shell in comparison to the DCP and limestone respectively (P ≤ 0.05). Performance was influenced (P ≤ 0.05) by particle size; with coarser particles BW and feed intake were increased (P ≤ 0.05). Tibia shear force and P content were reduced (P ≤ 0.001), whereas tibia shear energy, length, ash and Ca content were increased by substitution of DCP with DBM or bone meal (P ≤ 0.001; P ≤ 0.05). A significant difference was observed in the tibia length between the chicks fed oyster shell or limestone with different particles (P ≤ 0.05). Plasma P concentration was reduced in chicks were fed with DBM, bone meal and lower limestone particle size. Intestinal ALP activity was increased (P ≤ 0.001) in chicks which were fed DBM, bone meal, oyster shell or coarse particles of limestone. The P digestibility in chicks fed bone meal was lower than that of those fed DBM or DCP (P ≤ 0.01). Overall, gelatin removal from bone meal improved broiler bone characteristics through the P digestibility and intestinal ALP activity enhancement.

An optimal dietary non-phytate phosphorus level of broilers fed a conventional corn-soybean meal diet from 4 to 6 weeks of age

It is imperative to evaluate precise nutrient requirements of animals in order to optimize productivity and minimize feed cost and nutrient excretions. The current non-phytate phosphorus (NPP) recommendation for broilers is based on the papers published 30 years ago. However, today's commercial birds are quite different from those before 30 years. Therefore, the present experiment was conducted with growing male broiler chickens to evaluate an optimal dietary NPP level of broiler chickens fed a conventional corn-soybean meal diet from 4 to 6 weeks of age. The 1-day-old chicks were fed corn-soybean meal diet containing 0.39% NPP from 1 to 3 weeks of age. At 22 days of age, 360 birds were selected and randomly allotted by BW to one of 10 dietary treatments with six replicate cages of six birds per cage for each treatment. Birds were fed the P-unsupplemented corn-soybean meal basal diet and the basal diet supplemented with inorganic P as CaHPO4·H2O ranging from 0.00% to 0.45% with 0.05% increment from 4 to 6 weeks of age. The dietary NPP levels were 0.09%, 0.14%, 0.20%, 0.24%, 0.30%, 0.34%, 0.38%, 0.45%, 0.49% and 0.54%, respectively, and the dietary Ca level was fixed at 0.90% for all treatments. The results showed that average daily gain, serum inorganic P concentration, tibia bone strength, tibia ash percentage and P percentage, tibia bone mineral content (BMC) and density (BMD), middle toe ash percentage and P percentage, middle toe BMC, total body BMC and BMD were affected (P<0.0001) by dietary NPP level, and increased linearly (P<0.0001) and quadratically (P<0.003) as dietary NPP levels increased. Optimal dietary NPP levels estimated based on fitted broken-line models (P<0.0001) of the above indices are 0.21%, 0.29%, 0.29%, 0.29%, 0.29%, 0.31%, 0.29%, 0.30%, 0.27%, 0.29% and 0.28%, respectively. It is suggested that the total body BMC and BMD, and middle toe ash P and BMC might be new, sensitive and non-invasive criteria to evaluate the dietary NPP requirements of broilers. The optimal dietary NPP level would be 0.31% for broiler chickens fed a conventional corn-soybean meal diet from 4 to 6 weeks of age.

Toward improved phosphorus efficiency in monogastrics-interplay of serum, minerals, bone, and immune system after divergent dietary phosphorus supply in swine

Phosphorus (P) is of vital importance for many aspects of metabolism, including bone mineralization, blood buffering, and energy utilization. In order to identify molecular routes affecting intrinsic P utilization, we address processes covering P intake, uptake, metabolism, and excretion. In particular, the interrelation of bone tissue and immune features is of interest to approximate P intake to animal's physiology and health status. German Landrace piglets received different levels of digestible phosphorus: recommended, higher, or lower amounts. At multiple time points, relevant serum parameters were analyzed and radiologic studies on bone characteristics were performed. Peripheral blood mononuclear cells were collected to assess differential gene expression. Dietary differences were reflected by serum phosphorus, calcium, parathyroid hormone, and vitamin D. Bone reorganization was persistently affected as shown by microstructural parameters, cathepsin K levels, and transcripts associated with bone formation. Moreover, blood expression patterns revealed a link to immune response, highlighting bidirectional loops comprising bone formation and immune features, where the receptor-activator of NF-κB ligand/receptor-activator of NF-κB kinase system may play a prominent role. The modulated P supplementation provoked considerable organismal plasticity. Genes found to be differentially expressed due to variable P supply are involved in pathways relevant to P utilization and are potential candidate genes for improved P efficiency.

Comparison of 3 phytases on energy utilization of a nutritionally marginal wheat-soybean meal broiler diet

The net energy (NE) value may be a better measure than apparent metabolizable energy (ME) of the effect of supplemental phytase on energy utilization in broilers. The present study was conducted to assess the impact of 3 microbial phytases supplemented at an unconventionally high level (1,000 FTU/kg feed) on performance and NE of broilers using the indirect calorimetric method (IC). Four treatments included: 1) Control, formulated to be deficient in ME (12.35 MJ/kg in the starter diet; 12.56 MJ/kg in the grower diet), calcium (0.72% in the starter diet; 0.60% in the grower diet), and available phosphorus (0.25% in the starter diet; 0.20% in the grower diet); 2) control + intrinsically thermostable phytase A; 3) control + intrinsically thermostable phytase B; and 4) control + coated phytase C. A completely randomized design was employed. A total of 384 male broiler chicks were used, and each treatment had 6 replicates with 16 birds per replicate. The birds were reared until d 21 in floor pens with hardwood shavings. Thirty-two birds (8 birds per treatment) were randomly selected to determine heat production and NE (from 25-28 d) following a 3-d acclimatization in the respiratory chambers. Performance results at d 21 showed that supplementation with either of the 3 phytases improved body weight (P < 0.001) and feed intake (P < 0.05), and increased the relative weights of tibia ash (P < 0.05) and toe ash (P < 0.01). Phytases A and B increased the NE value of the diet (P < 0.05). It may be concluded that the negative effects imposed by calcium and available phosphorus down-specification can be compensated by phytase supplementation in general, and intrinsically thermostable phytases improve the ME and NE value. However, phytase did not reduce heat production, heat increment, or increase NE:ME in birds.

Relative availability of zinc in ground beef and soybean protein for young swine compared with zinc carbonate as the standard

The experimental objective was to determine the relative availability of endogenous Zn in soybean protein (SP) and cooked ground beef (GB) compared with the availability of Zn from ZnCO(3) for young swine. Crossbred pigs (4 trials with total n = 104) were weaned at an average age of 11 d, placed in metabolism cages, and allotted to 13 treatments. The basal semipurified negative control (NC) diet contained 2 mg of Zn/kg and wet-autoclaved spray-dried egg albumen (AEA) as the protein source. Reference diets were made by adding 3, 6, or 9 mg of Zn/kg from ZnCO(3) to the NC diet. The AEA in the NC diet was replaced with SP or GB to make diets with 3, 6, and 9 mg of Zn/kg from SP and GB. Positive control (PC) diets were made by adding 101 mg of Zn/kg from ZnCO(3) to the diets with 9 mg of Zn/kg from ZnCO(3), SP, or GB. Diets were mixed with deionized water and fed to appetite in gruel form every 3 h from 0800 to 2300 h. Pigs were weighed and blood samples were taken on d 7, 14, 21, and 28. Plasma concentrations of Cu, Fe, Zn, glucose, and urea N were determined. Total urine and fecal grab samples (Cr(2)O(3) in diets) were collected from d 7 to 14 and d 21 to 28 to determine Cu, Fe, Zn, and N apparent balance and energy utilization. On d 29, pigs were scored visually for parakeratosis and dosed orally with (65)Zn from ZnCl(2). Pigs were counted for whole body gamma radioactivity on d 29 and d 34 to 36, with Zn retention estimated by extrapolation to zero time. Pigs were killed on d 36 (NC on d 29). Samples of skin, tongue, and esophagus were taken for histological evaluation, and a tibia bone was excised for measurements and breaking strength. Pigs fed the diets with 9 mg Zn/kg from GB or ZnCO(3) were not different in Zn availability and retained about 70% Zn (apparent balance and (65)Zn) compared with 30% (P ≤ 0.05) for pigs fed the diet with 9 mg Zn/kg from SP. Also, pigs fed the diets with 9 mg Zn/kg from GB or ZnCO(3) had greater (P ≤ 0.05) growth performance, bone weight and breaking strength, % N retention, and % ME utilization, and smaller plasma urea N concentrations and parakeratosis scores (visual and histological) than pigs fed the diet with 9 mg Zn/kg from SP. Pigs fed the PC diets were not different in any response criteria. In conclusion, apparent Zn availability was not different from cooked GB and ZnCO(3), and Zn availability from cooked GB and ZnCO(3) was markedly greater than Zn availability from SP for young swine.