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.     

Urinary tract infections-microbial virulence determinants and reactive oxygen species

The human urinary tract is able to combat with the microbial invasion under normal circumstances. To cause urinary tract infection the organism has to evade the host defense mechanisms by possessing distinct properties which contribute to the virulence of the organism hence called virulence determinants Ninety percent of uncomplicated urinary tract infections are caused by Escherichia coli, hence the knowledge of the virulence determinants of this organism can be extrapolated to other uropathogenic organism as well. Virulence determinants of uropathogenic E. coli include adhesins, siderophore production, polysaccharide coating, hemolysin production, outer membrane proteins etc. The intestinal E. coli, which are the reservoir of E. coli for causing UTI, lack these virulence determinants. On the other hand these virulence determinants enable the organism to colonize and invade the urinary tract. In addition these are important in acquiring the nutrients in other wise nutrient deficient environment. Further, they also help the organisms in triggering an inflammatory response and hence bringing about pathological changes which leads to symptomatic UTI. Severity of symptomatic infections and tissue damage during the infective process depends upon the magnitude of the inflammatory response triggered by the uropathogen which in turn is dependent upon the amount of extrcellular release of reactive oxygen species by the phagocytic cells; hence role of antioxidants as an adjunct to antibiotics in the treatment of infective process needs to be evaluated further.     

Relative bio-availability and utilisation of phosphatic fertilisers as sources of phosphorus in broilers and layers

1. Different concentrations of non-phytate phosphorus (NPP, 2.5, 3.0, 3.5, 4.0 and 4.5 g/kg diet) were given to broilers (8 to 42 d of age) to establish regressions between dietary NPP concentration and body weight gain and tibia ash content. Second and third experiments were conducted to study the feasibility of utilisation of different phosphatic fertilisers [ammonium phosphate (AP), ammonium polyphosphate (APP), single super phosphate (SSP), NPK (17:17:17, NPK) and NP (28:28:0, NPK)] in commercial broilers (8 to 42 d) and White Leghorn layers (252 to 364 d). 2. Phosphatic fertilisers were incorporated both in broiler (10 g calcium and 4.5 g NPP/kg) and layer (35 g calcium and 3.5 g NPP/kg) diets by replacing dicalcium phosphate (DCP) in toto. 3. The logarithmic curves obtained for predicting the body weight gain and tibia ash content at different levels of NPP used in experiment 1 were Y = 156.27 + 2,468.8 logX (r2= 0.958) and Y = 530.82 + 144.26 log X (r2 = 0.916), respectively. 4. Body weight gain and food intake in broilers given APP- or NP-supplemented diets were comparable to these in the DCP-fed group. Feeding of NPK, AP or SSP resulted in significant depression in weight gain and food intake and high excreta moisture content. Food/gain, Ca and P contents in tibia ash and serum were not influenced by the use of phosphatic fertilisers as P sources in broiler diets. 5. Tibia ash content in broilers fed on diets containing fertilisers was either similar to or significantly higher than that in the DCP-fed group. Broilers on AP or SSP retained more P and had higher tibia ash content than those on DCP. AP, SSP or NPK caused degenerative and necrotic changes in liver, kidney and intestine of broilers. 6. Relative bio-availability of P from APP or NP was better for body weight gain than AP, SSP or NPK, while the reverse was true for bone calcification. 7. APP and NP gave hen-d egg production similar to that of DCP-fed layers. Food intake was significantly reduced in layers fed on diets containing fertilisers. However, food/egg mass, egg weight and serum Ca and inorganic P contents were not influenced by inclusion of fertilisers in layer diets. 8. Except for AP, inclusion of fertilisers in layer diets reduced shell weight and shell thickness compared with the DCP-fed group. However, no apparent eggshell defects were found which could be attributable to diet. 9. Results of these experiments suggest that APP and NP can be used as the sole source of P both in broiler and layer diets, replacing DCP in toto. However, when utilising these P sources in layers, due attention should be given to shell quality. Fertilisers containing high F (AP and SSP) or K (NPK) reduced performance in broilers and layers and caused microscopic changes in liver, kidney and intestine in broilers.     

In vitro culture, serologic and molecular analysis of Acanthamoeba isolated from the liver of a keel-billed toucan (Ramphastos sulfuratus)

Members of the genus Acanthamoeba are usually free-living amebae and are found in a variety of ecological niches including soil, fresh and brackish water, dust in air, filters of heating, ventilating, and air conditioning units, swimming pools and hot tubs, etc. Occasionally, they are also known to cause central nervous system infections in humans and other animals. We isolated into culture an amoeba from the liver tissue of a keel-billed toucan and identified it as Acanthamoeba sp. based on culture characteristics and immunofluorescent analysis. Further, we characterized the cultured amoeba and also the amoeba in the liver tissue as Acanthamoeba, genotype T4, by sequencing a diagnostic region of the nuclear small subunit ribosomal RNA gene.     

The stress of weaning influences serum levels of acute-phase proteins, iron-binding proteins, inflammatory cytokines, cortisol, and leukocyte subsets in Holstein calves

The purpose of our study was to investigate changes in immunological parameters induced by weaning stress (including milk restriction) in calves. Fifteen Holstein calves were subjected to weaning at 6 weeks of age. Blood samples were collected at -14, -7, -2, 1, 3, and 5 days post-weaning (DPW; 0 DPW = 42 days). Weaning caused significant (p < 0.01) increases in the neutrophil (NE):lymphocyte (LY) ratio at 5 DPW with a significant (p < 0.05) reduction of LYs. The concentration of acute-phase proteins (haptoglobin and serum amyloid A) also increased significantly (p < 0.05) at 3 and 5 DPW compared to -2 DPW. Levels of the iron-binding protein lactoferrin decreased significantly (p < 0.05) after weaning. Serum tumor necrosis factor-α and cortisol levels were elevated (p < 0.05) at 3 DPW, while those of serum interferon-γ decreased (p < 0.05) at 1 and 3 DPW compared to levels observed before weaning. Weaning significantly (p < 0.05) decreased the percentage of CD25⁺ T cells in the peripheral blood. In conclusion, weaning stress affected the NE:LY ratio along with the levels of acute phase proteins, lactoferrin, cortisol, and inflammatory cytokines in the peripheral blood of calves. Weaning stress may induce an acute phase response possibly through the elevation of cortisol production and modulation of inflammatory cytokines.     

Effect of dietary α -tocopherol concentration on performance and some immune responses in broiler chickens fed on diets containing oils from different sources

1. An investigation was carried out into the effects of dietary α-tocopherol (α-T) concentration and source of supplemental oil on performance, activity of anti-oxidative enzymes and some immune responses in broilers from day-old to 41 d of age. 2. Three dietary concentrations of α-T (10, 50 and 100 mg/kg) with three sources of supplemental oil (sunflower - SFO, palm - PMO and safflower - SAO) were provided using a 3 × 3 experimental design. 3. Body weight gain and food conversion efficiency were not affected by either interaction or concentrations of α-T and sources of oil in diet. 4. Concentrations of total protein, globulin, triglycerides and cholesterol in sera increased significantly with dietary α-T concentration irrespective of the source of oil. Significantly higher concentration of serum albumin was evident in broilers fed on the SFO-based diet and the concentration of globulin was higher in groups fed on those diets containing PMO and SAO. 5. The lipid peroxidation (LP), measured as MDA release, decreased with the concentration of α-T in a dose-related manner with SFO- and SAO-based diets, although not with the PMO-based diet. With different oil sources, LP was significantly lower with the PMO-based diet compared to the others. Activities of glutathione peroxidase and RBC catalase increased and heterophil: lymphocyte ratio was reduced with concentration of α-T for each source of oil tested. 6. Assays for humoral and cell-mediated immune responses indicated no effect of the source of dietary supplemental oil or interaction, although an increasing concentration of dietary α-T improved cell-mediated immune responses. 7. It is concluded that sunflower oil, palm oil and safflower oil can be used as sources of oil for broiler diets without having any effect on performance, immune responses or the activity of anti-oxidizing enzymes. Higher concentrations of dietary α-tocopherol (50 or 100 mg/kg) reduced lipid peroxidation activity and enhanced activities of anti-oxidative enzymes, they also improved the cell-mediated immune responses in commercial broilers.     

Nutrient intake, digestibility, and blood metabolites of goats fed diets containing processed jatropha meal

This study was conducted to record the ideal source and level of alkali treatment to treat jatropha meal (JM) and to determine the effect of inclusion of variously processed JM (pJM) on nutrient intake, digestibility, blood metabolites and hormonal status in goats. The JM was treated with 10 g/kg sodium chloride and 5 g/kg calcium hydroxide. The content of phorbol ester and hemagglutination (HA) activity of JM and pJM were assessed. A feeding trial for 90 days was conducted in short-haired multipurpose goats (n?=?15; five per group). The experimental animals were offered oat (Avena sativa) straw ad libitum throughout the experimental period of 90 days. Each group was assigned to one of the three diets, viz. R₁—soybean meal, R₂—sodium chloride (10 g/kg dry matter, DM), and R₃—calcium hydroxide (5 g/kg DM), with pJM substituting 250 g/kg DM of crude protein (CP) of control (R₁). At the end of the feeding period, digestion trial of 7 days was conducted. Blood samples were collected at the end of the experimental period to assess the blood metabolites and hormonal status. The phorbol ester and HA activity were reduced considerably in pJM. The intake of DM, organic matter, CP, and nitrogen-free extract were comparable among all the groups. However, the intake of ether extract was significantly higher in pJM-fed groups. The hemoglobin, packed cell volume, serum urea, triiodothyronine and testosterone contents decreased in R₂ and R₃ as compared to R₁. Concentration of glucose and activity of serum glutamic pyruvic transaminase and lactate dehydrogenase increased (P?<?0.01) in goats fed pJM. It was concluded that phorbol ester content and HA activity markedly decreased by processing JM with sodium chloride and calcium hydroxide. However, they were not reduced to the levels of safe feeding, as reflected in unusual values of blood metabolites among the experimental animals.     

Effect of an immunomodulator on the efficacy of an attenuated vaccine against avian pneumovirus in turkeys

Since 1997, avian pneumovirus (APV) has caused estimated annual losses of $15 million to the Minnesota turkey industry. In order to develop an attenuated live vaccine against APV, we serially passaged a Minnesota isolate of APV (APV/MN/turkey/1-a/97) in vitro in cell cultures for 41 passages. Laboratory experiments with this high-passage virus (P41) indicated that the attenuated virus provided immunogenic protection to turkeys against challenge with virulent APV, although some birds showed mild to moderate dinical signs after inoculation. To reduce the residual pathogenicity of P41, while maintaining its immunogenicity, we decided to vaccinate turkeys with P41 in the presence of an immunomodulator, S-28828 (1-n-butyl-2-ethoxymethyl-1H-imidazo[4,5-c]quinolin-4-amine-hydrochloride), which is a potent cytokine inducer. The combined inoculation of S-28828 (5 mg/kg body weight) and P41 resulted in a significant reduction in the incidence of virus-induced clinical signs in comparison with birds that received P41 without immunomodulator (P < 0.05). Only 17% of birds inoculated with S-28828 + APV P41 showed mild respiratory symptoms at 5 days postinoculation as compared with 46% of the vaccinated turkeys that did not receive S-28828. Vaccination with either P41 or with P41 + S-28828 protected turkeys against dinical signs and viral replication after challenge with virulent APV. These results indicate that immunomodulators, such as S-28828, may act as good vaccine adjuvants that can reduce the pathogenicity but maintain the immunogenicity of partially attenuated vaccines.     

Effect of nano-SiO2 on properties of wood/polymer/clay nanocomposites

Wood polymer nanocomposites (WPNC) based on nano-SiO₂ were prepared by impregnation of styrene acrylonitrile copolymer (SAN), SiO₂ nanoparticles modified with γ-trimethoxy silyl propyl methacrylate (MSMA), and nanoclay into wood. The structure of modified SiO₂ nanoparticles and WPNC was characterized by Fourier transform infrared spectroscopy (FTIR). XRD analysis showed the delaminated structure of SAN/SiO₂/clay-treated wood composites. The synergistic effect of nano-SiO₂ and nanoclay was investigated. Thermal stability of SiO₂ nanoparticles decreased after modification, while that of wood treated with SAN, SiO₂, and nanoclay improved. Morphological characteristics were examined by scanning electron microscopy (SEM). Mechanical properties, water uptake (%), dimensional stability, hardness, and flammability were found to improve due to incorporation of SiO₂ and nanoclay into wood polymer composites. Maximum improvement in properties was observed in the wood polymer composites containing SiO₂ and nanoclay at the ratio of 1:1.