Parâmetros zootécnicos e desenvolvimento da moela de frangos de corte em dietas de sorgo grão e a inclusão de carotenoides / Zootechnical parameters and gizzard development of broilers fed with sorghum grain and carotenoid supplementation

Objetivou-se avaliar a substituição do milho pelo sorgo grão, moído ou inteiro, e a inclusão de carotenoides sintéticos em rações de frangos de corte, sobre parâmetros zootécnicos e desenvolvimento da moela. Utilizaram-se 960 frangos, machos e fêmeas, da linhagem Cobb 500, que foram submetidos a quatro dietas: à base de milho (M), à base de sorgo moído (SM) ou ainda acrescido de carotenoides sintéticos (SMC) e à base de sorgo inteiro (SI). Foram avaliados peso vivo, consumo de ração, conversão alimentar, rendimento de carcaça e cortes, peso de moela. A ração de SI proporcionou maior desenvolvimento de moela, embora, aos sete dias, não tenha havido diferenças no peso vivo e na conversão alimentar entre as dietas. SM e SMC proporcionaram maiores valores de peso vivo aos 28 dias do que SI. As conversões alimentares real e tradicional aos 40 dias foram semelhantes para as rações de sorgo, com um melhor rendimento de carcaça em SM e SMC. O sorgo moído pode substituir integralmente o milho nas rações para frangos de corte, sem comprometimento de desempenho e rendimento de carcaça, e, na forma grão inteiro, é zootecnicamente viável.(AU)

This study aimed to evaluate the replacement of corn with ground or whole grain sorghum and the inclusion of carotenoids in broiler feed on zootechnical parameters and gizzard development. A total of 960 Cobb 500 broilers, half of each sex, were submitted to four feeds: ground corn (M), ground sorghum (SM) ground sorghum with carotenoid supplementation (SMC) and whole grain sorghum (SI). Body weight, feed intake and feed conversion, carcass and cuts yield, gizzard weight were evaluated. SI feed provided a greater development of gizzard, however at 7 days there were no differences in body weight and feed conversions between diets. SM and SMC provided higher values of body weight at 28 days than SI feed. Feed conversion at 40 days were the same for the sorghum feeds with a better carcass yield in SM and SMC. Ground sorghum can completely replace corn in broiler diets without compromising performance and carcass yield, and whole grain sorghum is zootecnaly viable.(AU)

The length of the feed restriction period affects eating behavior, growth performance, and the development of the proximal part of the gastrointestinal tract of young broilers.

We studied the effects of restricting the access to feed on the anticipatory eating behavior, growth performance, and the development of the proximal part of the gastrointestinal tract (GIT) in broilers. The experiment consisted in physical restriction of the access of broilers to feed for 0, 4, 6, or 8 h per day from 7 to 19 D of age. At 10, 13, 16, and 19 D of age, immediately before the start of the feed restriction (FR) period, 2 birds per cage were euthanized to evaluate crop and gizzard development. The experimental design was completely randomized, and the linear (L) and quadratic (Q) effects of fasting length on growth performance and GIT traits were determined. In addition, the effect of broiler age on GIT development was studied. From 7 to 19 D of age, ADFI (L, Q; P ≤ 0.05) and BW gain (L; P ≤ 0.01) decreased as the length of the FR period increased, with most of the differences observed with 6 or more hours of fasting. However, feed conversion ratio was not affected by FR length. The relative weight of the crop (% BW) and its fresh content increased (L; P ≤ 0.001) and the moisture of the digesta (%) decreased (L; P ≤ 0.001) as the FR period increased. The DM content (g) of the crop increased with FR, with most of the differences observed with 6 or more hours of fasting (L, Q; P ≤ 0.001). At 19 D of age, the Lactobacillus spp. count in the crop increased (L; P ≤ 0.05) with increase in the FR period. Fasting did not affect any gizzard trait at any age. In summary, physical restriction of the access to feed for 6 h or more reduced BW gain but did not affect feed conversion ratio in broilers from 7 to 19 D of age. Feed restriction for 4 to 8 h stimulated the anticipatory feeding behavior and crop development in broilers.

Influence of inclusion level of barley in wheat-based diets and supplementation of carbohydrase on growth performance, nutrient utilisation and gut morphometry in broiler starters.

1. The influence of barley inclusion level and supplementation of a multi-component non-starch polysaccharide degrading enzyme on performance and nutrient utilisation in broilers was investigated. Normal-starch hulled barley was evaluated with five levels of inclusion (0, 141, 283, 424 and 565 g/kg) in a wheat-based diet and two levels of enzyme supplementation (0 and 150 g/tonne of feed; a 5 × 2 factorial arrangement of 10 dietary treatments). All diets were equivalent in metabolisable energy and digestible amino acid contents. A total of 400, one-d old male broilers (five cages/treatment; eight birds/cage) were used in the experiment.2. Regardless of enzyme supplementation, weight gain (WG) increased up to 283 g/kg of barley and was reduced afterwards (P < 0.01). Increasing levels of barley resulted in greater (P < 0.001) gain per feed (G/F). Enzyme addition increased WG (P < 0.05) and G/F (P < 0.001) at each barley inclusion level.3. Birds fed diets with 0 and 565 g/kg barley showed the lowest and highest (P < 0.001to 0.05) digestibility for all nutrients measured, respectively. Digestibility of all nutrients was improved by enzyme supplementation at each barley inclusion level (P < 0.05). The nitrogen-corrected apparent metabolisable energy improved with increasing inclusion of barley (P < 0.001) and supplemental enzyme (P < 0.01). Increasing inclusion of barley increased the relative weight of gizzard (P < 0.001) and reduced jejunal digesta viscosity (P < 0.001). Supplemental enzyme (P < 0.001) reduced digesta viscosity.4. The optimum inclusion level of barley, with respect to growth performance, was 283 g/kg of diet. Increasing barley inclusion improved nutrient and energy utilisation, possibly through lowered digesta viscosity and better function of the gizzard. Feed efficiency and nutrient and energy utilisation can benefit from carbohydrase supplementation in barley-based diets, regardless of barley inclusion level.

Feed processing and structural components affect starch digestion dynamics in broiler chickens.

1. A 2 × 2 factorial design was used to test the hypothesis that impaired intestinal starch digestibility is attributable to rapid passage of digesta from the gizzard to the intestine, and that, compared to steam pelleting, increasing the availability of starch through extrusion cooking may alleviate the potential negative effect of rapid digesta flow on starch utilisation. 2. Thus, 7-d-old-broiler chickens were distributed to 48 cages and given a wheat-based (WB) pelleted diet containing either coarse oat hulls (OH-Pel) or fine cellulose (Cel-Pel) until d 19 to stimulate divergent development of the gizzard. Thereafter, both groups were further subdivided and challenged with a WB diet containing cellulose in either pelleted (Cel-Pel) or extruded (Cel-Ext) form on d 20 and 22. Either excreta or intestinal contents were collected at time intervals after feeding and analysed for marker and starch. 3. OH-Pel increased gizzard size and holding capacity. No excessively high starch levels (maximum 25 g/kg) were detected in the excreta. However, 8 h feed-deprived birds given Cel-Pel and challenged with Cel-Pel exhibited higher starch excretion and showed large individual variation during the first 135 min of collection. 4. Contrary to the OH-Pel group, more digesta and starch passed to the jejunum at 1 and 2 h and ileum at 2 and 3 h after feeding for birds given Cel-Pel, resulting in lower jejunal and ileal starch digestibility. 5. Increased starch gelatinisation through extrusion processing significantly improved starch digestibility regardless of gizzard function. However, at 1, 2 and 3 h after feeding, more digesta was retained in the foregut of birds given Cel-Ext. 6. The current data showed that starch degradation rate is associated with the flow of digesta which is linked to gizzard development, and that enzymatic hydrolysis of intact starch granules may be limited with more rapid feed passage through the gut.

Dietary sugarcane bagasse and coarse particle size of corn are beneficial to performance and gizzard development in broilers fed normal and high sodium diets.

An experiment was conducted to evaluate the effects of sugarcane bagasse (SB) and particle size on broiler performance, gizzard development, ileal microflora, litter quality, and bird welfare under a wet litter challenge model. A total of 672 one-day-old Ross 308 male broilers was allocated to 48 pens using a 2 × 2 × 2 factorial arrangement of treatments with corn particle size-coarse 3,576 µm (CC) or fine 1,113 µm (FC) geometric mean diameter, SB - 0 or 2% and sodium (Na) - 0.16 or 0.40% with increased Na level to induce wet litter. A 3-way particle size × Na × SB interaction (P < 0.05) was observed for weight gain at d 10. Birds fed FC showed a higher weight gain compared to birds fed CC when 0.40% Na without SB diet or 0.16% Na with 2% SB diet was offered. A significant particle size × SB interaction was observed at d 24 on feed conversion ratio (FCR; P < 0.001) and weight gain (P < 0.05). FCR was reduced by 2% SB supplementation in birds fed CC but increased in birds fed FC. Further, weight gain of birds fed 2% SB was higher in birds fed CC but not in those fed FC. On d 35, birds fed 2% SB had a higher weight gain (P < 0.001) compared to those without SB, and a SB × particle size interaction on relative gizzard weight (P < 0.05) and pH (P < 0.05) was present. SB reduced gizzard pH and increased the relative gizzard weight in birds fed the FC diet but not the CC diet (P < 0.05). Counts of ileal Bacillus spp. were increased in birds fed SB (P < 0.05) on d 24. No effects of SB and particle size on litter quality and bird welfare were observed, but higher Na increased litter moisture and footpad dermatitis (FPD) scores (P < 0.001). These findings suggest that SB independently or in combination with CC improves performance in older birds regardless of Na level in diets, possibly through improved gizzard development and gut microflora of birds.

Effect of dietary fiber levels on performance, gizzard development, intestinal morphology, and nutrient utilization in meat ducks from 1 to 21 days of age.

The objective of this experiment was to determine the effects of dietary fiber levels on growth performance, gizzard development, intestinal morphology, and nutrient utilization in Cherry Valley meat ducks. In total, 720 1-day-old ducklings were fed with starter diets (120 ducklings, 8 pens of 15 ducklings, on each diet) containing 6 levels of crude fiber (CF, 1.46, 3.09, 4.15, 6.18, 7.52, and 9.03%, based on analysis) for 21 d. Then, on d 22, ducks fed all of the starter diets were transferred to a grower diet (containing 4% CF) to examine the residual effect of starter dietary fiber levels until 35 d. Body weight (BW), body weight gain (BWG), feed intake (FI), feed to gain ratio (F:G) were recorded/calculated weekly. Ducks were sampled for gizzard development and intestinal morphology determination on d 7, 14, and 21. Nutrient utilization was assessed using 25- to 27-day-old ducks. The results showed that BW (d 21), BWG (d 15 to 21, d 1 to 21), and F:G (d 15 to 21, d 1 to 21, and d 1 to 35) were increased quadratically (P < 0.01), and FI (all periods except for d 22 to 35) was increased linearly (P < 0.01), when starter dietary CF levels increased from 1.46 to 9.03%. Ducks under 3.09% and 4.15% CF starter diets had decreased 1 to 35 d FI and F:G when compared to ducks under other starter diets. When compared to ducks fed 1.46% and 3.09% CF starter diets, ducks fed starter diet containing 7.52% CF had increased gizzard development, jejunal morphology, energy retention, excreta nutrients availability, and standardized ileal digestibility (SID) of Arg, Ile, Leu, Thr, Val, Asp, Ala, Glu, Gly, Pro, Ser, and total amino acids. In conclusion, meat ducks from 1 to 21 d of age could adapt to a wide range (3.09% to 7.52%) of dietary fiber levels.

Evaluation of ground grain versus pre- and post-pellet whole grain additions to poultry diets via a response surface design.

1. The objective of this study was to compare the effects of pre- and post-pellet whole grain wheat additions to diets on growth performance, gizzard and pancreas development, nutrient utilisation and starch and protein (N) digestibility coefficients in broiler chickens via an equilateral triangle response surface design. 2. The three apical treatments of the equilateral triangle comprised (1A) a standard diet containing 600 g/kg ground wheat, (2B) the same diet containing 600 g/kg pre-pellet whole wheat and (3C) the same diet containing 300 g/kg ground wheat and 300 g/kg post-pellet whole wheat. Seven blends of the three apical diets were located within the triangle to complete the design and a total of 360 male Ross 308 chicks were offered the ten experimental diets from 7 to 28 d post-hatch. Model prediction and response surface plots were generated with R 3.0.3 software. 3. The most efficient FCR of 1.466 was observed in birds offered an almost equal mixture of the pre- and post-pellet whole grain apical dietary treatments, which corresponded to 172 g/kg ground grain, 256 g/kg pre-pellet whole grain, 172 g/kg post-pellet whole grain in a diet containing 600 g/kg wheat. 4. The most efficient energy utilisation (ME:GE ratio of 0.766) was observed in birds offered a blend of the ground grain and pre-pellet whole grain apical dietary treatments which corresponded to a mixture of 384 g/kg pre-pellet whole grain and 216 g/kg ground grain. 5. Pre-pellet whole grain feeding generated the most pronounced responses in increased relative gizzard contents, reduced gizzard pH and increased relative pancreas weights. Consideration is given to the likely differences between pre- and post-pellet whole grain feeding.

Performance and digestive function of broiler chickens given grit in the diet.

1. A series of experiments were carried out to study the effect of grit on broiler performance, gizzard development and fate of grit in the digestive tract. 2. In Experiment 1, performance, gizzard weight and content of grit in the gizzard of broiler chickens given access to granite-type grit was investigated. In Experiment 2, the effect of grit stones on performance and gizzard development was assessed in diets with or without whole wheat. 3. In Experiment 3, the effect of grit in the form of zeolite, granite or marble on gizzard development and digestive tract grinding and passage was studied in diets with or without whole wheat. 4. Grit stones had no effect on performance of broiler chickens, which may be explained by the fact that grit stones did not stimulate gizzard development to the same extent as with other structural materials. 5. The lack of stimulation is at least partly due to the fact that a majority of the grit stones eaten pass through the small intestine without being retained in the gizzard. 6. Grit in the form of marble reduced feed intake and weight gain.

Developmental morphology study on the stomach of African ostrich chicks.

This study investigates the developmental morphology changes on the proventriculus and gizzard of African ostrich chicks using gross anatomy, and light and transmission electronic microscopy. The body weight; the weight of the proventriculus and gizzard; the thickness of simple tubular glands, muscularis mucosae, compound tubular glands, and muscular layer of the proventriculus; and the thickness of the gizzard glands and muscularis mucosae were measured on postnatal d one, 45, 90, and 334. Under transmission electronic microscopy, the oxynticopeptic cells, mucous cells, and endocrine cells were observed in the proventriculus on postnatal d one, 45, and 90. Our results revealed that the weights of the proventriculus and gizzard (relative to the body weight) both peaked on d 90, respectively, and declined thereafter. The thicknesses of the simple tubular glands, muscularis mucosae, compound tubular glands, muscular layer of the proventriculus, and gizzard glands increased with increasing bird age. However, the thickness of the muscularis mucosae in the gizzard peaked on d 90 and gradually decreased thereafter. The result of transmission electron microscopy revealed that the glands in the submucosa layer of the proventriculus did not differ from other cell types, aside from an increase in cell diameter and an increase in cytoplasmic content. A significant increase in the number of mitochondria and smooth endoplasmic reticulum was noted, as well as an in granules secreted by endocrine cells. Therefore, to improve brood rates of reared African ostrich chicks, feed management ought to be enhanced between postnatal d one and day 90.

Effects of dietary coarsely ground corn and 3 bedding floor types on broiler live performance, litter characteristics, gizzard and proventriculus weight, and nutrient digestibility.

The effects of zero or 50% dietary coarsely ground corn (CC) in pelleted and screened grower and finisher diets on broilers reared on 3 bedding floor types (plastic net [NET], new pine wood shavings litter [NEW], or old pine wood shavings litter [OLD]) on broiler live performance, litter characteristics, gizzard and proventriculus weight, and apparent ileal digestibility (AID) were studied in a 2 × 3 factorial arrangement of treatments. Fine corn was produced with a hammermill (271 µm) and CC with a roller mill (1145 µm). Utilization of CC reduced milling cost by 9.47 cents per MT with similar nutrient content of screened pellets. The 50% CC treatment exhibited improved (P ≤ 0.05) feed intake at 42 d (2.5%) and 49 d (3.0%), and BW (5.4%) and FCR from 28 d (1.4%). Birds on NEW litter exhibited improved (P < 0.05) BW at 28 and 35 d and 42 d FCR as compared to NET and 49 d FCR compared to NET and OLD. The 50% CC treatment exhibited increased (P < 0.05) gizzard weight but decreased proventriculus weight at 49 d. NEW litter birds exhibited increased (P ≤ 0.05) gizzard weight at 28 d and 49 d and decreased proventriculus weight as compared to NET at 49 days. The 50% CC treatment exhibited decreased (P ≤ 0.05) litter moisture at 35 and 42 d, litter N at 35 and 49 d, and litter pH at 49 days. OLD litter birds exhibited greater (P < 0.05) litter N at 14, 35, and 49 d, as well as litter moisture, pH, and ammonia concentration at 49 days. The 50% CC group also exhibited improved AID of nitrogen (P < 0.05). Broilers fed pelleted and screened diets containing 50% CC exhibited improved live performance and reduced litter moisture while use of NEW litter resulted in a somewhat similar effect, which indicated that consumption of NEW litter also facilitated gastric development and function.

Potential of pelleted wheat straw as an alternative bedding material for broilers.

Broiler chickens are commonly placed on wood shavings as litter, but alternative litter sources are required due to the scarcity of wood shavings in many parts of the world. This study aimed to compare pelleted straw, chopped wheat straw, wood shavings, rice hulls, and shredded paper as litter candidates. Three-hundred-sixty Ross 308 one-day-old male chicks were used in this study. There were 5 litter treatments with 6 replicate pens, each with 12 birds. The feed conversion ratio (FCR) of birds reared on pelleted straw was improved compared (P < 0.05) to that of birds raised on rice hulls, whereas it did not differ for birds placed on wood shavings, rice hulls, chopped straw, or shredded paper. It was observed that the birds reared on wood shavings had higher relative gizzard weight at d 24 compared to those reared on pelleted straw (P < 0.05). Gizzard pH and measured cecal bacterial groups were not affected by the type of bedding material. Cecal bacterial groups measured at d 10 were not affected by bedding material. Birds reared on pelleted wheat straw had a lower incidence of footpad lesions than those on chopped straw and shredded paper on d 24 (P < 0.001) and 29 (P < 0.01). Litter source did not affect the occurrence of breast blisters at d 24, 29, or 35. On d 24, 29, and 35, pelleted straw litter was less caked than chopped straw and shredded paper (P < 0.001) whereas no significant differences were observed among pelleted straw, wood shavings, and rice hulls. The study demonstrated the potential benefits to using pelleted wheat straw as a bedding material. Further assessment of pelleting of wheat straw and other materials on broiler health, performance, and welfare are needed to determine the economic benefits of pelleted litter.

Effects of feed form and dietary coarse ground corn on broiler live performance, body weight uniformity, relative gizzard weight, excreta nitrogen, and particle size preference behaviors.

In this 14-d cage study, the effects of feed form (mash and crumble) and 6 coarse ground corn ( CC: ) inclusions [0, 10, 20, 30, 40, and 50% CC that replaced fine corn ( FC: )] on broiler live performance, BW uniformity, gizzard weight, excreta nitrogen, and particle size preference were investigated. The geometric mean diameter by mass ( DGW: ) of mash diets increased from 422 µm to 431, 471, 509, 542, and 640 µm, respectively, as the percentage of CC increased. Feed intake and BW were decreased by CC and mash at 7 d. Interactions between feed form and CC were observed for feed conversion ratio ( FCR: ) at 7 d of age (P < 0.01), and feed intake (P < 0.05), BW (P < 0.01), and gizzard weight (P < 0.01) at 14 d of age. Feed intake for all CC inclusions in crumble diets was similar and exceeded (P < 0.01) that of mash diets at 14 d. Among mash diets, the 10 and 30% CC feed intake was greater (P < 0.05) than 40 and 50% CC with 0 and 20% CC intermediate. Crumble diets produced a similar BW but greater 14-d BW than mash diets (P < 0.01). Within mash diets, 40 and 50% CC produced a smaller BW (P < 0.01). The FCR at 7 d of CC inclusions in crumble diets was improved (P < 0.01) versus the same CC in mash diets. Within mash diets, 40% CC performed poorer than 0, 10, 20, and 30% CC diets with 50% CC diet intermediate (P < 0.01). Crumble diets improved FCR at 14 d, but CC worsened FCR. Gizzard weight at 14 d was not affected by CC in crumble diets, while it increased with CC in mash diets (P < 0.01). Excreta nitrogen was increased (P < 0.01) by crumble diets. These data demonstrated that pelleting and crumbling reduced the impact of CC, produced a more consistent feed intake, and reduced selective feeding, and that CC stimulated gizzard weight in a linear manner in mash diets.

Effect of different levels of rapeseed meal and sunflower meal and enzyme combination on the performance, digesta viscosity and carcass traits of broiler chickens fed wheat-based diets.

The aim of the present experiment was to examine the effect of different levels of rapeseed meal (RSM) and sunflower meal (SFM) and enzyme combination (endoxylanase and ß-glucanase) on the production performance, carcass quality, gizzard development and digesta viscosity of broiler chickens. The experimental design was a 3×2 factorial arrangement of treatments evaluating three diet types containing different levels of RSM and SFM (low (L), medium (M) and high (H)) and two levels of enzyme inclusion (0 or 100 g/tonne diet to provide 1220 U xylanase and 152 U ß-glucanase per kg diet). Broiler starter and grower/finisher diets were formulated, based on wheat and soya bean meal and containing 50, 50 and 80 g/kg RSM and 0, 50 and 60 g/kg SFM for L, M and H treatments, respectively, during starter period and 80, 80 and 120 g/kg RSM and 0, 80 and 100 g/kg SFM for L, M and H, respectively, during grower/finisher period, and each diet was fed ad libitum to eight pens of 20 male broilers each. During the starter period (1 to 21 days), birds fed the H treatment had lower (P0.05) on feed conversion ratio (FCR). During the grower/finisher phase (22 to 42 day) and over the entire period (1 to 42 day) birds fed the H treatment had lower (P0.05) between RSM and SFM inclusion level and enzyme supplementation were observed for any of the measured parameters at any period. Diet type and enzyme supplementation had no effect (P>0.05) on carcass traits, abdominal fat pad, breast meat yield and jejunal digesta viscosity. Diet type influenced (P=0.05) relative empty gizzard weight, where the H treatment had higher relative empty gizzard weight compared with the L treatment. Enzyme supplementation tended (P=0.10) to increase relative empty gizzard weight. The present data suggest that high inclusion of SFM and RSM negatively influenced broiler performance. Enzyme supplementation improved FCR at all levels of RSM and SFM included in this study, but did not recover the reduction in weight gain caused by high inclusion of RSM and SFM.

Influence of whole wheat feeding on the development of coccidiosis in broilers challenged with Eimeria.

A study was conducted to assess the effect of whole wheat (WW) feeding on performance, gizzard development, oocyst yield and intestinal lesion score of broilers challenged with Eimeria species. Diets (ground wheat (GW) and 300 g/kg WW replacing GW before or after pelleting) were offered ad libitum from day 1 or days 7-28 post-hatch. At 21 days of age, each dietary treatment was divided into two groups, one unchallenged control and the other inoculated with mixed species of coccidia (Eimeria acervulina, E. maxima and E. tenella). The results showed that heavier gizzards and higher mortality were observed in WW-fed birds in comparison to GW-fed birds. Interestingly, the pattern of mortality in different dietary treatments paralleled changes in gizzard size. Based on increased mortality, it is concluded that WW feeding exacerbated the severity of coccidiosis infection, possibly via a mechanism involving enhanced gizzard development.

Influence of feeding coarse corn on performance, nutrient utilization, digestive tract measurements, carcass characteristics, and cecal microflora counts of broilers.

The objective of the present study was to examine the effects of feeding coarsely ground corn on performance, digestive tract measurements, nutrient utilization, and cecal microflora counts in broilers. Five diets containing 600 g/kg of finely ground corn (hammer milled) or 150, 300, 450, and 600 g/kg of coarse corn (cracked in roller mill) replacing (wt/wt) finely ground corn were formulated. Each diet in mash form was offered ad libitum to 6 replicate cages of broilers (8 birds per cage) from d 11 to 35 posthatch. Weight gain increased (linear effect, P < 0.01) with increasing inclusion levels of coarse corn. Feed intake (quadratic effect, P < 0.05) increased at 150 g/kg of coarse corn inclusion, plateaued until 450 g/kg, and then increased again to 600 g/kg. Feed per gain increased (quadratic effect, P < 0.05) as inclusion of coarse corn increased to 300 g/kg and then decreased with further inclusion. Apparent metabolizable energy and total tract DM retention (quadratic effect, P < 0.01) was unaffected up to 300g/kg inclusion, and then decreased with further inclusion of coarse corn. Relative gizzard weight increased (linear effect, P < 0.05) with increasing inclusion of coarse corn. Inclusion of coarse corn had no effect (P > 0.05) on ileal digestibility of DM, N, and starch. Breast meat yield decreased (linear effect, P < 0.05 and abdominal fat increased (linear effect, P < 0.001) with increasing inclusion levels of coarse corn, but there was no effect (P > 0.05) on the carcass yield. A linear (P < 0.05) effect was observed for cecal microflora counts. Lactobacillus spp. and Bifidobacteria spp. counts increased and counts of Clostridium spp., Campylobacterium spp., and Bacteroides spp. decreased with increasing inclusion levels of coarse corn. The present data showed that feeding of coarse corn increased weight gain and gizzard size, and modified gut microflora profile toward beneficial species and that it can totally replace ground corn in broilers fed mash diets.

Evaluation of soybean meal source and particle size on broiler performance, nutrient digestibility, and gizzard development.

Although there have been several reports concerning the effects of particle size of cereal grains on productive performance of poultry, there is limited information about the effects of soybean meal (SBM) particle size on broiler performance. The objective of the present experiments was to evaluate the effects of SBM source and particle size on broiler performance, gizzard weight, and nutrient digestibility. The first experiment was a 2 × 2 factorial arrangement of 2 SBM sources: expeller-extracted (ESBM) and solvent-extracted (SSBM), and 2 particle sizes: coarse grind, 971 µm, and fine grind, 465 µm. The second experiment was a 2 × 2 factorial arrangement of 2 ESBM particle sizes: coarse grind, 1,290 µm, and fine grind, 470 µm, and 2 corn particle sizes: coarse grind, 1,330 µm, and fine grind, 520 µm. In the first experiment, there was an interaction (P < 0.05) between SBM source and particle size on BW at 49 d of age. No differences in BW were observed when birds were fed coarse SSBM or ESBM, whereas birds fed diets containing fine ESBM exhibited lower BW than birds fed diets containing fine SSBM. In the second experiment, fine-grind ESBM (P < 0.05) and corn (P < 0.01) produced greater 19-d BW than did coarse grind. A significant interaction (P < 0.01) between ingredient type and particle size revealed that chicks fed coarse particles of corn or ESBM exhibited higher protein digestibility compared with chicks fed only fine particles. Corn particle size had a greater effect on gizzard weight than ESBM particle size. Birds fed diets that contained coarse corn had larger gizzards than birds fed fine corn (P < 0.01), but differences in gizzard weight were not observed when birds were fed coarse or fine ESBM. Particles greater than 1,300 µm depressed BW but improved protein digestibility.

Influence of feeding sorghum on the growth, gizzard development and carcass traits of growing geese.

The aim of this trial was to study the influence of feed form on the performance, gizzard development and carcass traits of growing geese. Between 42 and 98 days of age, 360 geese (type Maxipalm(®)) were fed a diet containing 500 g sorghum/kg (nitrogen-corrected apparent metabolizable energy 12.6 MJ/kg, 15.1 g/kg CP). Birds were divided into three groups differing in feed form: complete pellets (Control group, n = 120); a coarse-ground meal (CG group, n = 120); or a mixture containing protein-rich pellets and sorghum whole grains (M group, n = 120). Feed intake per pen (40 birds/pen) was measured weekly between 42 and 98 days of age, and individual live weight (LW) was measured every 2 weeks. At 84 and 98 days of age, 12 birds were slaughtered in each group to measure the gizzard development and body traits. Irrespective of the goose sex, LW at 98 days was lower for the CG group than for the Control group (5555 v. 5888 g, P < 0.05 for males and 5039 v. 5215 g, P < 0.05 for females). The feed intake over the entire period was 5.5% higher in the M group (P < 0.05) than in the Control and CG groups but the feed conversion ratio (6.91, P > 0.05) was similar in the three groups. The gizzard development (as % of LW) was higher in birds of the CG group than those of the Control and M groups at 84 days of age (+13.98% and +13.51%, respectively; P < 0.05) but was similar in all three groups at 98 days of age (4.01%, P > 0.05). The relative liver development was lower in the birds of the CG group than those of the other two groups at 84 and 98 days of age (-20%, P < 0.001 and -10%, P < 0.05, respectively). The other body traits were similar in the three groups at both 84 and 98 days of age. The present results suggest that a simplified diet presented in the form of a mixture of sorghum whole grains and protein-rich pellets did not reduce the performance of growing geese.

Improving the efficiency of feed utilization in poultry by selection. 1. Genetic parameters of anatomy of the gastro-intestinal tract and digestive efficiency.

BACKGROUND: Feed costs represent about 70% of the costs of raising broilers. The main way to decrease these costs is to improve feed efficiency by modification of diet formulation, but one other possibility would be to use genetic selection. Understanding the genetic architecture of the gastro-intestinal tract (GIT) and the impact of the selection criterion on the GIT would be of particular interest. We therefore studied the genetic parameters of AMEn (Apparent metabolisable energy corrected for zero nitrogen balance), feed efficiency, and GIT traits in chickens.Genetic parameters were estimated for 630 broiler chickens of the eighth generation of a divergent selection experiment on AMEn. Birds were reared until 23 d of age and fed a wheat-based diet. The traits measured were body weight (BW), feed conversion ratio (FCR), AMEn, weights of crop, liver, gizzard and proventriculus, and weight, length and density of the duodenum, jejunum and ileum. RESULTS: The heritability estimates of BW, FCR and AMEn were moderate. The heritability estimates were higher for the GIT characteristics except for the weights of the proventriculus and liver. Gizzard weight was negatively correlated with density (weight to length ratio) of duodenum, jejunum and ileum. Proventriculus and gizzard weights were more strongly correlated with AMEn than with FCR, which was not the case for intestine weight and density. CONCLUSIONS: GIT traits were largely dependent on genetics and that selecting on AMEn or FCR would modify them. Phenotypic observations carried out in the divergent lines selected on AMEn were consistent with estimated genetic correlations between AMEn and GIT traits.

Ontogeny of ghrelin mRNA expression and identification of ghrelin-immunopositive cells in the gastrointestinal tract of the Peking duck, Anas platyrhynchos.

Ghrelin is an acylated peptide and an endogenous ligand for the growth hormone secretagogue receptor (GHS-R), and stimulates growth hormone release and food intake in mammals. Peking duck is a very fast growing species of poultry. Although the sequence and structure of ghrelin have recently been determined, the expression of ghrelin in Peking duck has not been studied. Here, we investigated the tissue expression and distribution of ghrelin by RT-PCR and immunohistochemistry, respectively, in Peking duck at different stages of development. Ghrelin mRNA expression was mainly detected in the proventriculus and proventriculus-gizzard junction. It was first expressed, but weakly, on embryonic day 14 (E14); the expression increased by embryonic day 21 (E21), and was maintained at high levels between post-hatching-day 1 (P1) and post-hatching-day 60 (P60). Weak expression of ghrelin mRNA was also found in the gizzard and duodenum. In the gastrointestinal tract of growing Peking duck in P60, the largest number of ghrelin-ip cells was detected in the epithelium of the compound tubular glands in the proventriculus and the next largest number was in the proventriculus-gizzard junction. Very few ghrelin-ip cells were located in the epithelium of the simple tubular glands adjacent to the gizzard. No ghrelin-ip cells were observed elsewhere in the gastrointestinal tract. Ghrelin-ip cells were found in embryos as early as day E21; at the same time, the compound tubular glands in the proventriculus had formed. The numbers of ghrelin-ip cells on P1 were similar to those of E21 embryos. However, on P60, high numbers of strongly stained ghrelin-ip cells were found to be scattered in the epithelium of the compound tubular glands in the proventriculus. The density of ghrelin-ip cells (cells/mm(2)) in the proventriculus on P60 was significantly greater than those of P1 and E21 embryos. These results demonstrate that ghrelin is expressed in the Peking duck gastrointestinal tract, especially in the proventriculus, from mid-late-stage embryos to growing period and suggested an involvement of ghrelin in the development and biology of the gastrointestinal tract of the Peking duck.

Shellfish dredging pushes a flexible avian top predator out of a marine protected area.

There is a widespread concern about the direct and indirect effects of industrial fisheries; this concern is particularly pertinent for so-called "marine protected areas" (MPAs), which should be safeguarded by national and international law. The intertidal flats of the Dutch Wadden Sea are a State Nature Monument and are protected under the Ramsar convention and the European Union's Habitat and Birds Directives. Until 2004, the Dutch government granted permission for ~75% of the intertidal flats to be exploited by mechanical dredgers for edible cockles (Cerastoderma edule). Here we show that dredged areas belonged to the limited area of intertidal flats that were of sufficient quality for red knots (Calidris canutus islandica), a long-distance migrant molluscivore specialist, to feed. Dredging led to relatively lower settlement rates of cockles and also reduced their quality (ratio of flesh to shell). From 1998 to 2002, red knots increased gizzard mass to compensate for a gradual loss in shellfish quality, but this compensation was not sufficient and led to decreases in local survival. Therefore, the gradual destruction of the necessary intertidal resources explains both the loss of red knots from the Dutch Wadden Sea and the decline of the European wintering population. This study shows that MPAs that do not provide adequate protection from fishing may fail in their conservation objectives.