Supplemental phosphorus can be completely replaced with microbial phytase in White Leghorn layer diets.

1. A study was conducted to assess the possibility of totally replacing supplemental phosphorus sources in White Leghorn (WL) layer diets (aged 28 to 45 weeks of age) with microbial phytase supplementation. One thousand commercial layers (HyLine White) of 28 weeks of age were housed in California cages fitted in open-sided poultry shed at the rate of 20 layers in each replicate. Ten replicates were randomly allotted to each treatment, and the respective diet was fed from 28 to 45 weeks of age.2. A control diet (CD) containing the recommended levels of non-phytate phosphorus (3.6 g/kg NPP) and four other test diets (2-5) having sub-optimal levels of NPP (2.4, 2.0, 1.6 and 1.2 g/kg), but with supplemental microbial phytase (600 FTU/kg) were prepared and fed for the trial duration.3. The layers fed with lower levels of NPP with phytase had the same laying performance as the group fed the CD. Egg production, feed efficiency, egg mass, shell defects, egg density, shell weight, shell thickness, ash content and breaking strength of the tibia and sternum were not affected by feeding the lowest concentration of NPP (1.2 g/kg) plus microbial phytase.4. Phytase supplementation in diets with sub-optimal levels of NPP (2.4, 2 and 1.6 g/kg) significantly improved the Haugh unit score compared to those fed the CD.5. It was concluded that supplemental phosphorus can be completely replaced with microbial phytase (600 FTU/kg) in a diet without affecting egg production, shell quality or bone mineral variables in WL layers (28 to 45 weeks).

Feed emulsifier improves the performance and nutrient digestibility in broiler chicken fed diets without antibiotic growth promoter.

1. A study was conducted to assess the impact of supplementing-graded concentrations of emulsifier on the production performance, gut microbial count, and digestibility of nitrogen and energy in broiler chicken fed diets without AGP.2. Male broiler chicks (n = 1500; Vencobb-430), aged one-day-old, were randomly allocated into six dietary groups each with 10 replicates of 25 birds each. A maize-soybean and meat and bone meal-based basal diet without antibiotic (AGP) growth promoter served as negative control (NC). The basal diet was supplemented with BMD (AGP, bacitracin methylene disalicylate-BMD 100 g/T), which served as the positive control (PC). Emulsifier was added to the NC diets at either 250 g/ton in all phases (250-All), 250 g in starter and grower phases, and 500 g in the finisher phase (250:250:500), 250 g in starter and 500 g in both grower and finisher phases (250:500:500) and 500 g in all phases (500 g-All).3. Two broilers per replicate were slaughtered to record carcase traits and gut microbial count on day 43. There was significant improvement in body weight gain (BWG) and reduced FCR in broilers fed 250:250:500 and 250:500:500 g emulsifiers compared to other treatment groups. Carcase traits and faecal microbial count did not differ among treatments. The inclusion of BMD significantly improved nitrogen (N) digestibility compared to the NC group. The digestibility of emulsifier-supplemented groups was similar to those fed by the BMD group except for the 500-All group, which was an intermediary between NC and other emulsifier-fed groups.4. It was concluded that supplementation with emulsifier (250:250:500 or 250:500:500) without antibiotic growth promoter significantly improved FCR and body weight gain similar to broilers receiving antibiotic growth promoter, which was associated with increased ileal digestibility of N and energy.

Higher concentrations of folic acid reduced the dietary requirements of supplemental methionine for commercial broilers.

Objective: An experiment was conducted to study the effect of supplementing DL methionine (DL Met) at graded concentrations on performance, carcass variables, immune responses and antioxidant variables in broiler chicken fed folic acid (FA) fortified (4mg/kg) low-methionine diet. Methods: A basal diet (BD) without supplemental DL Met, but with higher level (4 mg/kg) of FA and a control diet (CD) with the recommended concentration of methionine (Met) were prepared. The BD was supplemented with DL Met at graded concentrations (0, 10, 20, 30, 40 and 50% supplemental DL Met of CD). Each diet was fed ad libitum to 10 replicates of 5 broiler male chicks in each from 1 to 42 d of age. Results: Body weight gain (BWG) reduced, and feed conversion ratio (FCR) increased in broilers fed low-Met BD. At 30 and 20% inclusion of DL Met, the BWG and FCR were similar to those fed the CD. Similarly, supplementation of 10% DL Met to the BD significantly increased ready to cook meat yield and breast meat weight, which were similar to those of the CD fed broilers. Lipid peroxidation reduced, the activity of antioxidant enzymes (GSHPx and GSHRx) in serum increased and lymphocyte proliferation increased with increased supplemental DL Met level in the BD. The concentrations of total protein and albumin in serum increased with DL Met supplementation to the BD. Conclusion: Based on the data, it can be concluded that supplemental Met can be reduced to less than 50% in broiler chicken diets (4.40, 3.94 and 3.39g/kg, respectively in pre-starter, starter and finisher phases) containing 4 mg/kg FA.

Effect of dietary supplementation of zinc proteinate on performance, egg quality, blood biochemical parameters, and egg zinc content in White Leghorn layers.

A study was conducted to investigate the effects of zinc proteinate (Zn-P) on laying performance, egg quality, antioxidant indices, and egg zinc content in laying hens from 38 to 49 weeks of age. A total of 150 White Leghorn layers were randomly assigned to five treatments, each with six replicates with five birds per replication. Dietary treatments included a corn-soybean meal-based basal diet with no zinc addition and basal diet supplemented with Zn-P at 40, 80, 120, or 160 mg/kg of feed for 12 weeks. The analyzed zinc concentrations of the five diets were 29.5, 70.8, 110.2, 147.5, and 187.5 mg Zn/kg, respectively. Dietary Zn-P supplementation had no effect on feed intake and egg production. However, raising the zinc level improved egg weight (P < 0.01) and egg mass (P < 0.05) and lowered the feed conversion ratio (P < 0.05) during the later (46-49 weeks) period. The Zn-P supplementation also significantly (P < 0.05) increased Haugh units, egg shell strength, and shell thickness and had no influence on other egg quality parameters. Increasing zinc levels in the diet resulted in increase in egg zinc contents and serum zinc level. The serum triglyceride and LDL-cholesterol levels significantly decreased (P < 0.05) in Zn-P-supplemented groups. Supplementation of Zn-P significantly (P < 0.05) increased serum Cu-Zn-SOD activity and reduced MDA concentration. It could be concluded that dietary supplementation of higher levels of Zn-P, more than 80 mg/kg diet, significantly improved the egg zinc content, some egg quality traits, antioxidant activity, and serum zinc levels.

Effect of supplementing graded concentrations of non-phytate phosphorus on performance, egg quality and bone mineral variables in White Leghorn layers.

1. An experiment was conducted to determine optimal non-phytate phosphorus (NPP) concentrations for White Leghorn (WL) layers (22-72 weeks) fed diet containing 38 g Ca/kg. 2. Eight diets with graded concentrations (1.5-3.25 g/kg in increments of 0.25 g) of NPP were prepared. Each diet was fed to eight pen replicates containing 88 birds in each. Performance data was evaluated in three different phases (phase I-22-37 weeks, phase II-38-53 weeks and phase III-54-72 weeks). Optimum levels of NPP were determined by fitting a quadratic polynomial (QP) regression model. 3. Egg production (EP) was not affected (P = 0.059) by the concentration of NPP and interaction between NPP and diet phase was non-significant, indicating that the lowest concentration (1.5 g/kg diet) of NPP used in the study was adequate across the three phases. However, EP was influenced by phase (P < 0.001). 4. Optimum concentration of NPP for feed intake (FI) was estimated to be 1.5, 1.71 and 2.40 g/kg diet during phases I, II and III, respectively. FI per egg mass (EM) or feed efficiency (FE) responded quadratically with NPP and also differed significantly between phases. Optimum concentration of NPP for FE during phases I, II and III was 1.5, 2.56 and 2.32 g/kg diet, respectively. 5. Egg weight (EW), EM, shell weight and thickness were not affected by NPP concentration although all of these variables (except shell weight) were influenced by phases. 6. Breaking strength of tibia and Ca contents in tibia ash were not affected by the concentration of NPP, but bone ash and P contents in tibia ash were influenced (P < 0.001) by NPP. Predicted optimal concentrations of NPP for responses for tibia ash at 44 or 72 weeks, tibia ash P at 44 weeks and tibia ash P at 72 weeks were 1.55, 2.63 and 1.5 g/kg diet, respectively. 7. Based on the results, it was concluded that WL layers required 1.5 g, 2.63 g and 2.4 g, respectively/kg diet during phase I, II and III with the calculated daily intake of 137.3, 278.3 and 262 mg NPP/b/d.

Distinct abscisic acid signaling pathways for modulation of guard cell versus mesophyll cell potassium channels revealed by expression studies in Xenopus laevis oocytes.

Regulation of guard cell ion transport by abscisic acid (ABA) and in particular ABA inhibition of a guard cell inward K(+) current (I(Kin)) is well documented. However, little is known concerning ABA effects on ion transport in other plant cell types. Here we applied patch clamp techniques to mesophyll cell protoplasts of fava bean (Vicia faba cv Long Pod) plants and demonstrated ABA inhibition of an outward K(+) current (I(Kout)). When mesophyll cell protoplast mRNA (mesophyll mRNA) was expressed in Xenopus laevis oocytes, I(Kout) was generated that displayed similar properties to I(Kout) observed from direct analysis of mesophyll cell protoplasts. I(Kout) expressed by mesophyll mRNA-injected oocytes was inhibited by ABA, indicating that the ABA signal transduction pathway observed in mesophyll cells was preserved in the frog oocytes. Co-injection of oocytes with guard cell protoplast mRNA and cRNA for KAT1, an inward K(+) channel expressed in guard cells, resulted in I(Kin) that was similarly inhibited by ABA. However, oocytes co-injected with mesophyll mRNA and KAT1 cRNA produced I(Kin) that was not inhibited by ABA. These results demonstrate that the mesophyll-encoded signaling mechanism could not substitute for the guard cell pathway. These findings indicate that mesophyll cells and guard cells use distinct and different receptor types and/or signal transduction pathways in ABA regulation of K(+) channels.