Long-term effects of dietary calcium and phosphorus level, and feed form during rearing on egg production, eggshell quality, and bone traits in brown laying hens from 30 to 89 wk of age.

The effects of feeding strategies during rearing (0-16 wk) of brown laying hens on mid and end laying performance (30-89 wk) were studied. The rearing feeding strategies followed a 3 × 2 factorial arrangement with feed form; mash with inclusion of 3% finely ground wheat straw (MWS), crumbles with inclusion of 3% finely ground wheat straw (CWS), and crumbles with inclusion of 3% unground oat hulls as fiber sources (COH) at 2 dietary Ca and P levels (high or low Ca-P). Feed conversion ratio improved with COH and MWS compared with CWS from 30 to 59 wk. Rate of lay and egg mass production showed a feed form × Ca-P interaction from 60 to 89 wk. Low Ca-P led to a higher egg production, but only when COH and MWS were fed. BW at 89 wk was higher with CWS compared to COH and MWS. BW uniformity was better with COH compared to MWS at 51 wk and both CWS and MWS at 67 wk. Tibia characteristics were not clearly affected by treatment, although there was a feed form × Ca-P interaction on compression at 89 wk, where compression was lower with MWS and low vs. high Ca-P. Low Ca-P during rearing led to higher eggshell thickness, compared to high Ca-P at 45 wk of age, but breaking strength was lower with low vs. high Ca-P at 75 wk. Although eggshell quality was affected by Ca-P and there were some interactions with feed form at some ages, the effect was not consistent. There was no clear relationship between eggshell quality and tibia characteristics. It was concluded that feeding low Ca-P in combination with COH and MWS during the rearing period positively affects egg production during late lay. Also, dietary Ca-P levels, compared to commercial practice, can be lowered during rearing, as this will not affect eggshell quality and bone mineralization at later ages.

Proteolytic enzyme-treated seaweed co-product (Ulva laetevirens) inclusion in corn-soybean and European broiler diets to improve digestibility, health, and performance.

The impact of addition of an Ulva laetevirens (previously Ulva rigida) co-product treated with a broad-spectrum endo-protease when added to a standard corn-soy (S) based diet and a diet based on European protein sources (EU) on performance, in vivo digestibility and multiple gastrointestinal characteristics was investigated in broilers. In total, 624 Ross 308 one-day-old male broilers were fed one of 6 experimental diets (8 replicates) consisting of a basal diet (S or EU), or a basal diet including the U. laetevirens co-product (U) treated without (U-) or with (U+) a proteolytic enzyme. Starter diets contained 0 (wk 1) and 2.5 (wk 2), and the grower diets (wk 3 and 4) 5% seaweed co-product. In the last 2 wk, birds fed the S vs. EU grower diets showed a higher BW, BWG, and FI, as well as a lower FCR (-0.05 g/g) in wk 3 (P < 0.05). Heavier gizzards (+13%; P < 0.001) and heavier gizzard contents (+92%; P < 0.001) were observed in birds fed the EU vs. S diets, as well as longer villi (+8%; P = 0.010). U diets had a higher water holding capacity than the basal diets (+19%). In wk 4, U inclusion resulted in increased FCR (+0.06 g/g; P < 0.001), water intake (+7%; P < 0.001), and duodenal cross section (+5%; P = 0.033). Enzyme treatment did not affect digestibility of any nutrients, except for ash which was increased in birds fed U+ vs. U- diets (+60%; P < 0.001). U in S diets led to higher, and U in EU diets led to lower apparent pre-cecal digestibility of all nutrients (P < 0.001 for all nutrients). Although for both diet types performance was decreased, dietary U. laetevirens inclusion had different effects when added to a standard corn-soy diet and a diet based on European protein sources. No obvious health effects were observed, leading to the conclusion of the absence of performance of health promoting bioactive components in the U. laetevirens co-product, or of diminishing of these effects due to the proteolytic enzyme treatment.

A proteolytic enzyme treatment to improve Ulva laetevirens and Solieria chordalis seaweed co-product digestibility, performance, and health in broilers.

To explore the potential use of seaweed co-products for broiler diets, this study investigates whether an enzyme treatment of seaweed co-products improves performance, in vivo digestibility and health in broilers. In total, 360 Ross 308 male broilers were fed one of 5 experimental diets: a basal diet, or a basal diet including the U. laetevirens or S. chordalis co-product, with or without proteolytic enzyme treatment of the seaweed, using 6 replicate pens of 12 birds each. The starter (d 0-13) and grower (d 14-21) diet contained 5 and 10% (w/w) seaweed product, respectively. A general linear model with contrast statements was used after model assumptions and goodness of fit were evaluated through normal distribution of residuals. Inclusion of seaweed in the broiler diets increased body weight gain (+14%; P = 0.002), and feed intake (+12%; P = 0.001) in the third week of the experiment. Birds fed the U. laetevirens compared to the S. chordalis diets had a higher body weight gain (+11%; P = 0.007), and a lower feed conversion ratio (FCR; -7%; P < 0.001). Seaweed inclusion reduced apparent pre-cecal digestibility of all nutrients (P < 0.05). Birds fed U. laetevirens vs. S. chordalis diets had a 10% reduced villus length (P < 0.001). Enzymatic treatment reduced the digestibility of most nutrients, and increased crypt depth in birds fed the U. laetevirens diets, whereas the opposite was observed for the birds fed the S. chordalis diets (Seaweed × Enzyme P = 0.035). Untreated vs. treated seaweed in the diets led to lower (-60%) plasma Interleukin-13 levels (P = 0.035). In conclusion, the proteolytic enzyme treatment of the seaweed co-products did not improve performance nor health-related parameters, and reduced digestibility of the diets. Dietary inclusion of U. laetevirens co-products did improve performance based on growth and FCR, whereas inclusion of S. chordalis did not. Inclusion of U. laetevirens in broiler diets slightly reduced duodenal villus length and crypt depth. The inflammation response was strongly reduced, specifically in birds fed the untreated U. laetevirens diet, making the U. laetevirens co-product of interest for future research.

The effects of dietary calcium and phosphorus level, and feed form during rearing on growth performance, bone traits and egg production in brown egg-type pullets from 0 to 32 weeks of age.

In a 3 × 2 factorial arrangement, effects of feed form (crumbles (CWS), mash (MWS), both with inclusion of 3% finely ground wheat straw, or crumbles with inclusion of 3% oat hulls (COH)), and dietary Ca and P (high and low Ca-P) from 0 to 16 wk of age were studied on growth performance, bone characteristics, and gizzard development of egg-type pullets. The cross-over effect of feeding strategy during rearing on laying performance and egg shell quality was studied from 19 to 32 wk of age. From 0 to 16 wk, ADG, ADFI, and feed conversion ratio (FCR) were improved with CWS and COH compared to MWS, but ADG and FCR were improved with MWS compared to CWS and COH from 11 to 16 wk. Uniformity of BW till 11 wk, and tibia breaking strength at 6 and 16 wk were higher with CWS and COH compared to MWS. Tibia ash content at 11 wk and relative empty proventriculus + gizzard weight (EPG) were lower with CWS and COH compared to MWS, also relative EPG at 11 and 16 wk was higher with COH compared to CWS. At 25 wk BW was lower with MWS compared to CWS and COH, but BW was equal for all treatments at 32 wk. The FCR for egg production was improved with COH compared to MWS. Egg shell parameters were not affected by feed form during rearing. Low Ca-P decreased BW uniformity at 6 wk, relative keel bone weight and ash content at 11 wk, tibia ash content at 11 and 16 wk, increased relative EPG at 6 wk, and improved egg shell quality at 32 wk of age. It was concluded that feeding CWS and COH compared to MWS increased growth performance, but had no clear cross-over effect on egg production. Low dietary Ca-P led to a lower bone mineralization during rearing, nevertheless improved egg shell quality at 32 wk.

The effects of coarse and wet feeding on performance parameters, gastrointestinal tract and tibia traits, and digesta phytase activity in egg-type pullets, either fed a low or moderate phosphorus diet.

In a 2 × 2 × 2 factorial design, the effects of dietary non-phytate phosphorus (NPP) levels, 0.17% (low) and 0.33% (moderate), diet moisture (dry and wet), and diet particle size (coarse and fine), were studied on egg production, characteristics of gastrointestinal tract (GIT) and tibia, digesta pH, and phytase activity in layer pullets (16 to 28 wk of age). The low NPP diet increased average daily water intake (ADWI) to ADFI ratio (4.2%) from 16 to 17 wk, but decreased this ratio (2.8%) from 23 to 27 wk. It decreased ADFI (1.5%) and egg mass production (3.8%) from 19 to 22 wk. It decreased egg weight (0.29 g) and ADWI (2.1%) from 23 to 27 wk. At 22 wk, the GIT relative empty organ weights were (g/kg BW) higher for proventriculus + gizzard (0.96), duodeneum (0.94), and jejunum + ileum (1.95) with the low vs. moderate NPP diet. The low NPP diet decreased digesta phytase activity in crop and proventriculus+gizzard at 28 wk. The wet diet increased ADFI, ADWI, and ADWI/ADFI ratio from 16 to 27 wk, egg mass production (3.0%) from 19 to 22 wk, and egg weight (0.45 g) from 23 to 27 wk. The wet diet also increased digesta phytase activity in proventriculus+gizzard. The coarse diet decreased ADFI from 19 to 22 wk (1.7%) and 23 to 27 wk (1.2%). The coarse diet caused reduced egg mass production (2.6%) from 23 to 27 wk. Egg shell breaking strength was increased on the coarse diet (0.9 Newton). The coarse diet increased ADWI/ADFI ratio from 16 to 27 wk, and increased relative gizzard weight by 1.95 and 0.81 g/kg BW at 22 and 28 wk, respectively. The coarse diet increased jejunal/ileal pH with 0.16 units at 28 wk. None of the tested parameters affected tibia characteristics. It was concluded that a low NPP diet did not clearly affect the studied parameters. The wet diet increased ADFI, ADWI, and egg production. The coarse diet increased ADWI, egg shell breaking strength, relative gizzard weight, and reduced ADFI and egg production.

Butyrate presence in distinct gastrointestinal tract segments modifies differentially digestive processes and amino acid bioavailability in young broiler chickens.

The hypothesis was tested that butyrate presence in the digesta of distinct gastrointestinal tract (GIT) segments of broilers leads to differential effects on digesta retention time, gut morphology, and proteolytic enzymatic activities, ultimately resulting in differences in protein digestibility. A total of 320 male day-old Ross 308 broilers were randomly assigned to 5 dietary treatments: 1) control (no butyrate), 2) unprotected butyrate (main activity in the crop and gastric regions), 3) tributyrin (main activity in the small intestine), 4) fat-coated butyrate (activity in the whole GIT) and 5) unprotected butyrate combined with tributyrin, each replicated 8 times. Rapeseed meal was used in combination with a fine dietary particle size in order to challenge the digestive capacity of young broilers. Birds were dissected at 22, 23, and 24 d of age and samples of digesta at various GIT locations as well as tissues were collected. Butyrate concentration varied significantly across GIT segments depending on treatment, indicating that the dietary contrasts were successful. The apparent ileal digestibility of methionine tended to increase when butyrate and/or propionate was present in colonic and cecal contents, possibly due to modifications of GIT development and digesta transit time. Butyrate presence in the digesta of the crop, proventriculus and gizzard, on the contrary, decreased the apparent ileal digestibility of several amino acids (AA). In addition, butyrate presence beyond the gizzard elicited anorexic effect that might be attributable to changes in intestinal enteroendocrine L-cells secretory activities. The present study demonstrates that, in broilers, effects of butyrate on digestive processes are conditioned by the GIT segment wherein the molecule is present and indicates its influence on digestive function and bioavailability of AA.

Diet structure, butyric acid, and fermentable carbohydrates influence growth performance, gut morphology, and cecal fermentation characteristics in broilers.

An experiment with 288 male (Ross 308) 1-d-old broilers was conducted to test the hypothesis that a coarse diet supplemented with butyric acid (BA) and fermentable carbohydrates (FC) improves performance of broilers with a poorly digestible protein source. The interaction effects of diet structure (fine or coarse), FC supplementation (with or without), and BA supplementation (with or without) in a poorly digestible diet based on rapeseed meal (RSM) were tested in a factorial arrangement of 8 (2×2×2) dietary treatments. The coarseness of the diet affected feed intake (FI) (P<0.001), BW gain (P=0.001), and the feed conversion ratio (FCR) (P=0.001) positively. Broilers fed the coarse diets had, on average, 14% heavier gizzards and 11, 7, 5, and 6% lower relative empty weights of the crop, duodenum, jejunum, and ileum, respectively, compared with those fed the fine diets. Dietary coarseness resulted in, on average, 6% greater ileal protein digestibility, 20% lower gizzard pH, 19% greater villus height, 18% lower crypt depth, and 23% reduced cecal branched chain fatty acids (BCFA) compared with chickens fed the fine diets. Broilers fed BA-supplemented diets had an improved FCR (P=0.004) and decreased crypt depth (P<0.001) compared with those fed diets without BA. Fermentable carbohydrate supplementation did not influence growth performance, gut development, or contents of total BCFA and total biogenic amines in the cecal digesta (P>0.05). Supplementation with FC, however, decreased the cecal concentration of spermine by approximately 31% compared with broilers fed diets without FC (P=0.002). In conclusion, feeding a coarse diet supplemented with BA improved performance of broilers fed a diet containing a poorly digestible protein source. The negative effects of a poorly digestible protein source can thus be partly counterbalanced by coarse grinding and BA supplementation in the diet.

Effects of phytase supplementation on phosphorus retention in broilers and layers: a meta-analysis.

Phytase, a widely used feed additive in poultry diets, increases P availability and subsequently reduces inorganic-P supplementation and P-excretion. Phytase supplementation effect on P-retention in poultry has been investigated, but the effect sizes were highly variable. The present study's objective was to conduct several meta-analyses to quantitatively summarize the phytase effect on P-retention in broilers and layers. Data from 103 and 26 controlled experiments testing the phytase effect on P-retention were included in 2 separate meta-analyses for broilers and layers, respectively. The mean difference calculated by subtracting the means of P-retention for the control group from the phytase-supplemented group was chosen as an effect size estimate. Between-study variability (heterogeneity) of mean difference was estimated using random-effect models and had a significant effect (P < 0.01) in both broilers and layers. Therefore, random-effect models were extended to mixed-effect models to explain heterogeneity and obtain final phytase effect size estimates. Available dietary and bird variables were included as fixed effects in the mixed-effect models. The final broiler mixed-effect model included phytase dose and Ca-to-total-P ratio (Ca:tP), explaining 15.6% of the heterogeneity. Other variables such as breed might further explain between-study variance. Broilers consuming control diets were associated with 48.4% P-retention. Exogenous phytase supplementation at 1,039 FTU/kg of diet increased P-retention by 8.6 percentage units on average. A unit increase of phytase dose and Ca:tP from their means further increased P-retention. For layers, the final mixed-effect models included dietary Ca, age, and experimental period length. The variables explained 65.9% of the heterogeneity. Layers receiving exogenous phytase at 371 FTU/kg were associated with a 5.02 percentage unit increase in P-retention. A unit increase in dietary Ca from its mean increased P-retention, whereas an increase in the experiment length and layer's age decreased P-retention. Phytase supplementation had a significant positive effect on P-retention in both broilers and layers, but effect sizes across studies were significantly heterogeneous due to differences in Ca contents, experiment length, bird age, and phytase dose.

Development and evaluation of a dynamic model of calcium and phosphorus flows in layers.

Phosphorus is an essential nutrient involved in most metabolic processes. Most of the interest in Ca metabolism relates to eggshell formation. Although the eggshell is composed of Ca carbonate, metabolism of both Ca and P is closely related such that a deficiency in one can interfere with proper utilization of the other. To understand Ca and P metabolism properly, modeling can be of paramount importance. A new dynamic and mechanistic model of P and Ca metabolism in layers has been developed to simulate diurnal changes in Ca and P and the hourly requirement of the layer for those minerals. The model consists of 8 state variables representing Ca and P pools in the crop, stomachs, plasma, and bone. The flow equations are described by Michaelis-Menten or mass action forms. An experiment that measured Ca and P uptake in layers fed different Ca concentrations during shell-forming days was used for model evaluation. The experiment showed that Ca retained in body and egg decreased from 62.5 to 50.5% of Ca intake when the Ca in diet was increased from 25 to 45 mg/g of feed. The model simulations were in agreement with the trend. Predictions of Ca retention in bone and egg were 63.2, 56.1, and 55.3% for low, medium, and high dietary Ca concentrations. The experimental results showed that P retention in body and egg increased significantly from 11.5% of absorbable P intake at the lowest Ca inclusion concentration to 24.1% at the highest. The model also predicted an increase in P retention in bone and egg from 8.4 to 25.4% of absorbable P intake at the lowest and highest concentration of Ca inclusion, respectively. The advantage of the model is that absorption and utilization can be monitored on an hourly basis and that adjustments can be made accordingly. The model successfully showed how the availability of one mineral affects the utilization of the other and is a useful tool to evaluate feeding strategies aimed at reducing P excretion to the environment in poultry manure.

Effect of nutrient dilution on feed intake, eating time and performance of hens in early lay.

1. An experiment with 480 ISA Brown layers was conducted to measure the effect of dietary energy (11.8, 11.2 and 10.6 MJ/kg) and non-starch polysaccharides (NSP) (128, 146 and 207 g/kg) concentration, soluble NSP content (64 and 85 g/kg), particle size distribution of the NSP fraction (fine and coarse) and feed form (mash and crumble) on feed intake, eating time and egg performance of laying hens in early lay (from 18 to 26 weeks of age). Twelve experimental diets were tested, each replicated 4 times. 2. Laying hens in early lay that were fed low- or high-NSP diets were able to compensate for 10% dietary dilution by 9.5 and 4.9% higher feed intakes, respectively. Feeding crumble or coarsely ground mash did not affect feed intake. 3. Eating time of the hens fed the undiluted diets increased over the experimental period from 16.4 to 24.6% of the observation period, but was not affected by sand or grit addition, particle size distribution or feed form. Feeding high-NSP diets increased eating time by 22%. 4. Egg performance and body weight gain of the hens that were fed low-NSP or high-NSP diets were similar or better compared to the undiluted diets, whereas coarse grinding of the diets showed 7 to 10% lower egg performance and weight gain. Egg performance and weight gain were not affected by feed form. 5. It is concluded that hens in early lay, fed energy-diluted diets, by adding sand or grit (low-NSP) or NSP-rich raw materials (high-NSP) to the control diet, were able to increase their feed intake, resulting in energy intake and egg performance comparable to the control group. Supplementing diets with insoluble NSP also decreased eating rate. Prolonged eating time using insoluble NSP could be useful in reducing feather pecking behaviour.

Coccidiosis immunization: effects of mushroom and herb polysaccharides on immune responses of chickens infected with Eimeria tenella.

An experiment was conducted to investigate the effects of polysaccharide extracts (E) of two mushrooms, Lentinus edodes (LenE) and Tremella fuciformis (TreE), and an herb, Astragalus membranaceus (AstE), on the immune responses of chickens infected with Eimeria tenella. A total of 180 broiler chickens were assigned to nine groups: three groups were fed with each of the extracts (LenE, TreE, and AstE), three groups were fed with the extracts and immunized with live oocyst vaccine (LenE+V, TreE+V, and AstE+V), a group was immunized with the vaccine only, and there were two controls (E. tenella-infected and noninfected groups). The oocyst vaccine was given at 4 days of age, and the extracts (1 g/kg of the diet) were supplemented from 8 to 14 days of age. At 18 days of age, all birds except those in the noninfected group were infected with 9 x 10(4) sporulated oocysts. The results showed that at 7 days postinfection (p.i.), birds fed the extracts without vaccination had lower body weight (BW) gain than those given the vaccine only. However, the extracts in conjunction with the vaccine significantly enhanced BW gain of the infected chickens compared with the vaccine group. Of the three extracts, LenE and TreE showed a better growth-promoting effect. The extracts largely increased oocyst excretion of droppings during the primary response postvaccination. The cecal peak oocyst output and lesion scores measured at 7 days p.i. were higher in the groups fed the extracts than in the group immunized with the vaccine only, whereas those of the groups fed with the extracts and immunized with the vaccine were not significantly different from the vaccine group. Of the three extracts, both LenE- and AstE-fed groups showed lower cecal oocyst output. Thus, as compared with the extracts, the live, attenuated vaccine showed better results with significantly increased immune response in coccidial infected birds. The polysaccharide extracts may prove useful against avian coccidiosis, and, particularly when they are used in conjunction with vaccine, they have shown preliminary promise against the experimental coccidial infection.

Effects of mushroom and herb polysaccharides, as alternatives for an antibiotic, on growth performance of broilers.

(1) This in vivo trial was conducted to study the effects of polysaccharide extracts of two mushrooms, Lentinus edodes (LenE) and Tremella fuciformis (TreE), and a herb, Astragalus membranaceus (AstE) on growth performance, and the weights of organs and the gastrointestinal tract (GIT) of broiler chickens. (2) Three extracts (LenE, TreE and AstE) were supplemented at inclusion rates of 0.5, 1, 2, 3 and 4 g/kg from 7 to 14 d of age and compared with an antibiotic treatment group (20 mg/kg, virginiamycin (VRG) as well as a group of non-supplemented birds. (3) Body weight (BW) gain, feed intake and feed conversion ratio (FCR) of the extract-supplemented groups were not significantly different from those of the antibiotic group. Significant effects of type of extract and concentration on growth performance were found from 7 to 28 d of age. Generally, birds fed with LenE showed higher BW gain and lower FCR from 7 to 28 d of age than those fed with TreE and AstE and 2 g/kg LenE was considered the optimal inclusion rate for enhanced broiler growth. However, the extracts had no significant effect on the relative weights of organs and GIT compared with the antibiotic group. (4) The birds fed the extracts showed better growth performance than the non-supplemented birds, but were not significantly different from those fed VRG. Of the three extracts, LenE appeared to be a potential growth promoter. Future studies are needed to investigate whether the extracts can be used as alternatives for antibiotic growth promoters in challenged birds, and to elucidate the mechanisms for potentially enhanced growth performance in poultry.

Effects of mushroom and herb polysaccharides on cellular and humoral immune responses of Eimeria tenella-infected chickens.

We investigated the effects of polysaccharide extracts from 2 mushrooms, Lentinus edodes (LenE) and Tremella fuciformis (TreE), and an herb, Astragalus membranaceus (AstE), on cellular and humoral immune responses of Eimeria tenella-infected chickens. A total of 150 broiler chicks were assigned to 5 treatment groups: 3 groups were infected with E. tenella and fed with extracts (LenE, TreE, and AstE), and 2 control groups were infected with or without E. tenella. The 3 extracts were given at the level of 1 g/kg of the diet from 8 to 14 d of age. Specific systemic and cecum mucosal antibody production, proliferation of splenocytes, and peripheral T and B lymphocytes were measured during the 3 wk following Eimeria infection. A significantly higher production of specific IgA, IgM (at d 14 and 21 postinfection), and IgG (at d 21 postinfection) were detected in the Eimeria-infected groups fed with the extracts than in the infected group not fed with the extracts. Of the 3 extracts, TreE stimulated a slightly higher production of specific IgM (P = 0.052), and a significantly higher IgG production at 21 d postinfection. The cecal antibody production showed a similar trend to that of serum antibodies. The overall mean levels of cecal-specific IgA and IgG of the groups fed with extracts were significantly higher at 14 and 21 d postinfection compared with the group not fed with extracts. Of the 3 extracts, the AstE-fed group showed the highest IgG production at d 7 postinfection. Both TreE- and LenE-fed groups had significantly higher IgM and IgG levels compared with the AstE group at d 21 postinfection. The extract-fed groups also showed a significantly higher antigen-specific proliferation of splenocytes at 14 and 21 d postinfection compared with the group not fed with the extracts. The overall mean of erythrocyte rosette-forming cells (ERFC %) (at d 14 and 21) and erythrocyte-antibody-complement cells (EAC %) (at d 14) of the groups fed with the extracts was significantly higher compared with the group not fed the extracts. It is concluded from this study that supplementation with mushroom and herb extracts resulted in enhancement of both cellular and humoral immune responses in E. tenella-infected chickens.

Effects of mushroom and herb polysaccharides, as alternatives for an antibiotic, on the cecal microbial ecosystem in broiler chickens.

An in vivo experiment was conducted to study the potential prebiotic effects of mushroom and herb polysaccharide extracts, Lentinus edodes extract (LenE), Tremella fuciformis extract, and Astragalus membranaceus Radix extract, on chicken growth and the cecal microbial ecosystem, as compared with the antibiotic Apramycin (APR). This investigation was carried out in terms of a dose-response study. The chickens were naturally infected with avian Mycoplasma gallisepticum prior to the experiment. The BW gain, cecal pH, viscosity, and predominant microbial populations were measured 1 wk after the extract and APR treatments. The extracts and APR significantly stimulated growth of the chickens infected with avian Mycoplasma gallisepticum. The average BW gain of the groups fed with the extracts was significantly lower than that of the antibiotic group. The extracts had no significant effect on cecal pH. However, cecal viscosity and microbial populations were significantly affected by feeding extracts and antibiotic. In contrast to APR, the extracts stimulated the number of the potentially beneficial bacteria (bifidobacteria and lactobacilli), while reducing the number of the potentially harmful bacteria (Bacteroides spp. and Escherichia coli). Of the 3 extracts, LenE was associated with the most cecal bifidobacteria and lactobacilli. With each increase in the LenE dose, birds tended to have higher BW gain and total aerobe and anaerobe counts. Numbers of predominant cecal bacteria, in particular, E. coli, bifidobacteria, and lactobacilli, were significantly increased with increases in the LenE dose. It would seem that these specific mushroom and herb polysaccharide extracts hold some promise as potential modifiers of intestinal microbiota in diseased chickens.

Effect of a Chinese herb medicine formulation, as an alternative for antibiotics, on performance of broilers.

1. A total of 720 female broiler chicks was used to test the effects of 4 dietary concentrations of a Chinese herbal medicine (CHM) formulation (0.25, 0.5, 1 and 2g/kg), as an alternative for virginiamycin (VRG), on growth performance in broilers. 2. A total of 72 birds from non-supplemented, VRG and 0.5 g/kg CHM groups was selected and killed and the relative weights of the intestinal segments were assessed. 3. The CHM dietary treatments produced increased body weight gain at 7 to 21 d of age but not at 21 to 28 d of age compared with the non-supplemented and VRG groups. The CHM groups had a higher feed intake and a higher feed conversion ratio (FCR) than the VRG group between 21 and 28 d. 4. The dissection results showed that the liver colour of the birds in the CHM group varied less between animals than that of the VRG and the non-supplemented groups. Neither CHM nor VRG had any significant effects on either liver or intestinal tract weights. 5. It was concluded that the birds of the CHM group had better growth performance from d 7 to 21 but not thereafter. Further experiments are needed to elucidate the mechanisms underlying enhanced growth performance by CHM in broilers.

Comparative analysis of village chicken production in two farming systems in Burkina Faso.

This study aimed to describe and compare village chicken production in two farming systems in Burkina Faso. The systems were those in which crops and livestock production were, respectively, the most important. A rapid rural appraisal preceded a monitoring study in which data were collected fortnightly for 2 months. The study revealed that village chickens are used as sacrifices, gifts and objects of exchange for traditional medicine, or are sold for a little money under both systems. Chicken production is a free-range procedure in both farming systems, but there are differences in management. On average, the flock size was 33.5 +/- 3 birds, of which 57% were chicks. During the period of 2 months in the rainy season, the overall mortality was relatively low (8.8% +/- 1.5) but mortality in chicks was high (31.7%). The main cause of financial loss in the village chickens was mortality, which represented up to 84% of the total exits. The hatching rate and mortality in young chicks differed significantly (p < 0.05) between the two farming systems.

In vitro fermentation characteristics of two mushroom species, an herb, and their polysaccharide fractions, using chicken cecal contents as inoculum.

In vitro fermentabilities of two mushrooms (Lentinus edodes--LenS; Tremella fuciformis--TreS), an herb (Astragalus membranaceus--AstS), and their polysaccharide fractions (LenE, TreE, and AstE) were investigated using microflora from chicken ceca. Polysaccharides were extracted using the hot water method. The mushrooms had lower polysaccharide yields (8 to 10%) than the herb (31%). Fermentation kinetics were determined using the in vitro cumulative gas production technique. End-products, such as gas, volatile fatty acids (VFA), and ammonia, were also determined. The gas profiles of intact materials were similar for AstS and LenS. The TreS had a diphasic digestion pattern. The extracts had similar profiles to the intact materials though gas production rates were faster. Intact materials tended to produce less VFA than the extracts though LenS and AstE had the highest total VFA production overall. Intact materials contained more protein than the extracts, and therefore resulted in more branched-chain fatty acids and ammonia. Fermentation kinetics and end-point products demonstrated differences in availability of substrates between the mushrooms and herb. These medicinal mushroom and herb materials, particularly their polysaccharide extracts, show promise in altering microbial activities and composition in chicken ceca. In vivo experiments are necessary for confirmation of this hypothesis.

Interaction between ambient temperature and supplementation of synthetic amino acids on performance and carcass parameters in commercial male turkeys.

An experiment with male turkeys was conducted to test the hypothesis that turkey production performance responds positively to extra crystalline amino acid supplementation (lysine, methionine, and threonine) when subjected to a high ambient temperature regimen (HT) in the grower period. Two diets were formulated to provide lysine, methionine, and threonine concentrations that either 1) met the breeder recommendations or 2) contained 10% higher lysine and methionine concentrations from 22 to 134 d of age and 10% higher threonine concentration from 22 to 68 d of age. Both diets were fed at two temperatures (15 or 25 C) from 42 d of age onward. At 134 d of age, turkeys on the HT had generally lower BW than those on the low temperature regimen (LT). Up to 68 d of age and from 106 to 134 d of age, feed intake of turkeys on the HT was significantly lower than that of turkeys on the LT. Up to 42 d of age, feed conversion ratio (FCR) of turkeys on the HT were significantly lower than those of turkeys on the LT. Significant treatment interactions were observed from 22 to 41 d of age. Turkeys fed the amino acid-supplemented diets on the LT had significantly reduced FCR, whereas those on the HT did not respond. From 69 to 105 d of age, turkeys on the HT that were fed the supplemented diets had significantly increased FCR, but there were no dietary effects among turkeys on the LT. There were no consistent diet effects on growth performance or carcass yields. Breast meat yields of turkeys on the LT were higher (33.5 vs 32.1%), and drum yields were lower (12.7 vs 13.0%), than those of turkeys on the HT. There were no significant amino acid balance x ambient temperature effects on processing yields. The hypothesis of this experiment could be rejected as production performance did not respond positively to extra supplementation of lysine, methionine, and threonine when subjected to an HT.

Dietary unsaturated fatty acids affect antibody responses and growth of chickens divergently selected for humoral responses to sheep red blood cells.

The effect of linoleic and linolenic acid on antibody (Ab) responses to SRBC and BSA and on growth performance were studied in pullets of three genetically different laying lines. Pullets were fed one of three diets: a control diet, a linoleic acid-enriched diet, or a linolenic acid enriched-diet. The linoleic and linolenic acid enriched-diets were the control diet enriched with either sunflower oil or linseed oil. Two chicken lines divergently selected for high (H) and low (L) Ab responses to SRBC, and a randombred control (C) line were used. Total Ab responses to SRBC were not affected by diet, but in the H line a tendency for higher IgG titers to SRBC after primary immunization were found when birds were fed the linoleic diet. The humoral response to BSA was significantly affected by a line by immunization by diet interaction. In the H line birds, the linoleic diet significantly enhanced Ab titers to BSA as compared to the normal diet and linolenic acid-enriched diet. The linolenic acid-enriched diet significantly decreased Ab titers to BSA in the C line birds. No dietary effects on the titer to BSA were found in the L line birds. During the first 3 wk of life, the linolenic acid-enriched diet resulted in reduced BW gain of H line birds. After that period, no effects of diet on BW gain was found. It is concluded that modulation of Ab responses of poultry to T cell-dependent antigens by essential fatty acids is affected by genotype. The relationship between magnitude of Ab responsiveness, BW, and essential fatty acids is discussed.