Effects of dietary enzymes on performance and intestinal goblet cell number of broilers exposed to a live coccidia oocyst vaccine.

An experiment was conducted to evaluate the effects of dietary enzymes on performance, tibia ash, and intestinal goblet cells of broilers administered a live coccidia oocyst vaccine (Coccivac B, Schering Plough, Kenilworth, NJ). Cobb 500 straight-run broilers were obtained and one-half of the chicks were sprayed with the live coccidia oocyst vaccine. Chicks were weighed and placed in battery brooders with respect to nonvaccinated or vaccinated group according to dietary treatment. The 8 dietary treatments were a positive control (0.90% Ca and 0.45% available P), a negative control (NC; 0.80% Ca and 0.35% available P), NC + phytase (PHY), NC + protease (PRO), NC + xylanase (XYL), NC + PHY+ PRO, NC + PHY + XYL, and NC + PHY + PRO + XYL. A diet × vaccination interaction (P > 0.05) was not observed for feed intake or BW gain. Feed conversion ratio was improved (P ≤ 0.05) in birds fed NC + PHY + XYL compared with NC. Vaccination reduced (P ≤ 0.05) feed intake and BW gain from d 0 to 18. Tibia ash was reduced (P ≤ 0.05) in the NC and PRO or XYL diets. Vaccination increased goblet cell numbers in the duodenum of birds fed XYL, whereas no differences were found in goblet cell numbers between nonvaccinated and vaccinated birds in other dietary treatments, which resulted in a diet × vaccination interaction (P ≤ 0.05). Protease decreased and NC + PHY+ PRO increased goblet cells in the jejunum at d 7, which resulted in a diet × vaccination interaction (P ≤ 0.05). At d 18, NC + PHY + XYL was the only diet in which vaccination decreased goblet cells in the jejunum, resulting in a diet × vaccination interaction (P ≤ 0.05). The data indicate that NC + PHY + XYL improved the feed conversion ratio in broilers fed corn-soybean meal diets. The vaccination × dietary enzyme interaction altered the number of goblet cells in the small intestine. Dietary enzyme supplementation did not alleviate reductions in growth performance associated with the use of a live coccidia oocyst vaccine.

Enzymes as feed additive to aid in responses against Eimeria species in coccidia-vaccinated broilers fed corn-soybean meal diets with different protein levels.

This research aimed to evaluate the effects of adding a combination of exogenous enzymes to starter diets varying in protein content and fed to broilers vaccinated at day of hatch with live oocysts and then challenged with mixed Eimeria spp. Five hundred four 1-d-old male Cobb-500 chickens were distributed in 72 cages. The design consisted of 12 treatments. Three anticoccidial control programs [ionophore (IO), coccidian vaccine (COV), and coccidia-vaccine + enzymes (COV + EC)] were evaluated under 3 CP levels (19, 21, and 23%), and 3 unmedicated-uninfected (UU) negative controls were included for each one of the protein levels. All chickens except those in unmedicated-uninfected negative controls were infected at 17 d of age with a mixed oral inoculum of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Live performance, lesion scores, oocyst counts, and samples for gut microflora profiles were evaluated 7 d postinfection. Ileal digestibility of amino acids (IDAA) was determined 8 d postinfection. Microbial communities (MC) were analyzed by G + C%, microbial numbers were counted by flow cytometry, and IgA concentrations were measured by ELISA. The lowest CP diets had poorer (P < or = 0.001) BW gain and feed conversion ratio in the preinfection period. Coccidia-vaccinated broilers had lower performance than the ones fed ionophore diets during pre- and postchallenge periods. Intestinal lesion scores were affected (P < or = 0.05) by anticoccidial control programs, but responses changed according to gut section. Feed additives or vaccination had no effect (P > or = 0.05) on IDAA, and diets with 23% CP had the lowest (P < or = 0.001) IDAA. Coccidial infection had no effect on MC numbers in the ileum but reduced MC numbers in ceca and suppressed ileal IgA production. The COV + EC treatment modulated MC during mixed coccidiosis infection but did not significantly improve chicken performance. Results indicated that feed enzymes may be used to modulate the gut microflora of cocci-vaccinated broiler chickens.

Dietary betaine increases intraepithelial lymphocytes in the duodenum of coccidia-infected chicks and increases functional properties of phagocytes.

Betaine is used by cells to defend against changes in osmolarity. We examined relationships among betaine, osmolarity and coccidiosis. In the first experiment, chicks were fed corn-soy diets containing 0.0, 0.5 or 1.0 g/kg betaine; half were challenged with Eimeria acervulina (Cocci). Cocci decreased weight gain and feed efficiency and increased the osmolarity of the duodenal and jejunal mucosa (P < 0.01). Betaine decreased osmolarity of the duodenum (P < 0.01), especially in Cocci-challenged birds. Cocci increased the thickness (P = 0.04) of and number (P < 0.01) of leukocytes in the duodenal lamina propria especially at high betaine levels (interaction P = 0.05). Villi height was decreased by Cocci (P = 0.05) and this was ameliorated by 1.0 g/kg betaine (interaction P = 0.04). Intraepithelial leukocyte numbers were increased by Cocci (P < 0.01) especially at 0.5 and 1 g/kg betaine. Peritoneal macrophages or peripheral blood heterophils were incubated in media with an osmolarity of 200, 310, 600 or 900 mOsmol and 0.0, 0.1, 0.5 or 1.5 mmol/L betaine (4 x 4 factorial) for 6 h and then E. acervulina were added. In general, phagocytosis and NO release were decreased and interleukin (IL)-1 and IL-6 release were increased in hyperosmotic media compared with isosmotic media. Betaine (0.1 mmol/L) increased NO release by heterophils (P = 0.04) and tended to increase (P < 0.1) NO release from macrophages. The chemotaxis of monocytes toward chemotactic factors released by heterophils was increased by betaine. Increased chemotaxis of monocytes and NO release by macrophages may explain the decreased intestinal pathology but increased leukocyte numbers that were observed when betaine was fed during a Cocci infection.

Dietary betaine accumulates in the liver and intestinal tissue and stabilizes the intestinal epithelial structure in healthy and coccidia-infected broiler chicks.

The aim of this experiment was to study the patterns of betaine accumulation into intestinal tissue, liver and plasma of broiler chicks with or without coccidial infection. The chicks were raised on a corn-based, low-betaine diet with or without 1000 ppm betaine supplementation and with or without intestinal microparasite (Eimeria maxima) challenge to the age of 21 days. Plasma, liver, intestinal tissue and digesta of non-challenged (NC) birds and plasma and intestinal tissue of coccidiosis challenged (CC) birds were analysed for betaine content. NC birds were also analyzed for homocysteine in plasma and S-adenosylmethionine (S-AM) in liver. The jejunal epithelium was histologically examined for the presence of coccidia and the crypt-villus ratio was measured. Dietary betaine supplementation decreased the plasma homocysteine concentration but had no effect on liver S-AM of NC birds. The data suggest that chicks on a low-betaine diet accumulate betaine into the intestinal tissue. When the diet was supplemented with betaine, betaine accumulated heavily into liver and to a lesser degree into intestinal tissue. The concentration of betaine in jejunal and ileal digesta was low suggesting that dietary betaine was mainly absorbed from the proximal small intestine. The coccidial challenge decreased the concentration of betaine in the liver, but greatly increased that in the intestinal tissue. The crypt-villus ratio was decreased by the dietary betaine supplementation in healthy and challenged chicks, suggesting that dietary betaine both protects the jejunal villi against coccidial infection and also stabilizes the mucosal structure in healthy broiler chicks. These results support our earlier findings suggesting that betaine is likely to act as an important intestinal osmolyte in broiler chicks.

The effect of thiamin deficiency on amino acids in the brain, liver, and plasma of the turkey.

The present study was conducted to determine the effect of thiamin deficiency (TD) on amino acids in brain, liver, and plasma. Twenty-seven 1-wk-old female turkeys were assigned to TD or control groups. Experimental birds were fed a TD diet; control birds received the same diet with thiamin at levels recommended by the National Research Council. Chromatographic analysis at 12 days of age found altered levels of amino acids in selected brain areas and liver of TD birds. Proline was increased in the TD archistriatum and liver. Leucine was elevated in the TD hypothalamus, medulla-pons, midbrain thalamus, and cerebellum. Threonine was lower in the hippocampus, but was increased in the liver of TD birds. Glutamine declined in the TD hippocampus, but glutamate increased in the TD liver only. Urea decreased and valine increased in the TD medulla-pons. Aspartic acid and serine decreased in the TD liver. These results indicate that dietary TD does alter amino acids in these tissues.

Efficacy of lateral ventricular injection of epinephrine, cyproheptadine, or adenosine triphosphate on feed intake in thiamin-deficient turkeys.

In previous work, thiamin deficiency (TD) resulted in decreased brain levels of adenosine triphosphate (ATP) and epinephrine, but serotonin (5-HT) was increased in the turkey. The goal of the present study was to determine whether the introduction of calculated levels of epinephrine, ATP, or cyproheptadine into the lateral ventricle could affect feed intake of TD birds. Adenosine triphosphate, epinephrine, and cyproheptadine (5-HT antagonist) were injected into the lateral ventricle of TD and control birds. These injections did not alter feed intake in the control birds. Cyproheptadine and ATP decreased feed intake in the 1st h in the TD birds as compared with sham-injected TD birds (P less than .05), but epinephrine had no effect. The results indicate replacement or inhibition of a single altered neurochemical does not increase short-term feed intake in TD birds.

Effect of thiamin deficiency on energy metabolites in the turkey.

The effects of thiamin deficiency on selected energy-related metabolites was investigated. A basal diet (B) was formulated to be 11% of NRC recommended level of 2 mg/kg of thiamin. Thiamin was added to this basal diet to generate the control diet (C). Twenty one-week-old female turkeys were fed either the B or C diet. On days four and five of the experiment, food intake was decreased significantly in B fed turkeys (P < 0.05). Plasma and brain samples were collected at this time. Brains were dissected and analyzed for ATP, ADP, uric acid, free fatty acids, glucose, and GABA. Adenosine triphosphate and the ATP/ADP ratio were decreased in the hindbrain (medulla-pons area) of thiamin deficient birds (P < 0.01). Uric acid was increased (P < 0.001) and free fatty acids were decreased (P < 0.0005) in the plasma of thiamin deficient birds. Based on the data, changes in ATP and ATP/ADP levels may be related to the anorectic behavior exhibited by the thiamin deficient bird.