Fabiano Dahlke

Effects of corn particle size and physical form of the diet on the gastrointestinal structures of broiler chickens

The objective of this experiment was to investigate the effects of different particle sizes, expressed as Geometric Mean Diameter (GMD) of corn (0.336mm, 0.585mm, 0.856mm and 1.12mm) of mash and pelleted broiler chicken diets on the weight of the gizzard, duodenum and jejunum+ileum; on the pH of the gizzard and small intestine and on the characteristics of the duodenal mucous layer (number and height of villi and crypt depth) in 42-day-old broilers. The physical form and the particle size of the diet had no significant effect on gizzard and intestine pH (p > 0.05). A greater gizzard weight was seen in the birds receiving pelleted diet and particle size of 0.336mm (p < 0.008). However, for the particle sizes of 0.856 and 1.12 mm, a greater weight was found in birds that received mash diet (p < 0.039 and p < 0.006, respectively). Also, gizzard weight was greater with increasing corn GMD independent of the physical form of the diet. In the mash diet, the increase in particle size promoted a quadratic response in the weight of duodenum and jejunum + ileum. The pelleted diet promoted a greater number of villi per transverse duodenum cut (p < 0.007) and greater crypt depth (p < 0.05). As the particle size increased, there was a linear increase of villus height and crypt depth in the duodenum, irrespective of the physical form of the diet.

Dietas de baixa proteína no desempenho de frangos criados em diferentes temperaturas

The objective of this work was to evaluate broilers performance, from 42 to 49xa0days, fed on low-protein diet and reared under different temperatures. Three hundred and sixty male broilers from Cobb-500 strain were randomly housed in a 3x3 factorial arrangement (environmental temperature of 20, 25 and 32oC and crude protein levels of 18.0, 16.5 and 15.0%) with four replicates of ten birds each. Performance and efficiency of nitrogen retention were impaired in broilers fed on low-protein diets and reared under temperature of 32oC. Carcass, as well as thigh and drumstick increased in birds reared at hot temperature yield, however other parts yield, and abdominal fat deposition were not altered by the studied factors. Drumstick and thigh protein composition decreased in broilers reared under heat stress, while fat composition increased. Protein levels did not affect carcass composition. Low-protein diet impairs broiler performance in heat-exposed broilers from 42 to 49xa0days. However, broilers can be fed on low-protein diets under temperatures of 20 or 25oC, because these temperatures did not affect broilers performance, carcass quality, and they promoted lower nitrogen excretion.

Tamanho da Partícula do Milho e Forma Física da Ração e Seus Efeitos Sobre o Desempenho e Rendimento de Carcaça de Frangos de Corte

The experiment was conducted to evaluate the effect of different corn particle size, expressed as geometric mean diameter (GMD)(0.336 mm, 0.585mm, 0.856 mm and 1.12 mm) and two diet forms (mash-M and pellets-P) on performance and carcass yield of broilers from 21 to 42 days of age. M diets, produced with 0.336 mm of GMD resulted in lower feed intake (FI) (p<0.001), lower weight gain (WG) (p<0.001) and worse feed efficiency (FE) (p<0.001) than 0.336 mm P diets. M and P diets with other GMD did not show differences in performance. When particle size was evaluated itself, increments in GMD resulted a linear increase on WG and a quadratic increase on FI and FE. Neither form of diet nor particle size influenced carcass and leg+drumstick yields, although breast yield decreased with M diet,0.336 mm GMD (p<0.001).

Desempenho de Frangos de Corte Alimentados com Ovo em Pó

A experiment was conducted to study the addition of dried whole eggs (DWE) in broilers diets from 1 to 28 days of age in two phases (1to 7 and 8 to 28 days). From 1 to 7 days the birds received the diets with 0, 5, 10, 15 and 20% DWE and from 8 to 28 days of age the birds were assigned in a factorial arrangement 2x5 (2 levels of DWE - 0% and 5% - and the five previous levels). From 1 to 7 days of age birds fed control diet without DWE showed better weight gain and those fed the highest level of DWE showed the worst feed conversion. In the second phase (8 to 28 days) no interaction was found between treatments and also performance, gut weight and gut length were not affected by treatments. The results obtained suggest that the addition of DWE does not results in beneficial effects in broiler diets.

Desempenho, eficiência de utilização dos nutrientes e estrutura do trato digestório de pintos de corte alimentados na fase pré-inicial com rações de diferentes formas físicas

This experiment was conducted to evaluate the effect of different physical form of pre-starter diet on performance, nutrient utilization and development of gastrointestinal tract of broiler chicks during the first week of age. A total of 150-day-old male broiler chicks was allotted to a completely randomized design with three treatments and five replicates of 10 birds each. Treatments consisted of three physical forms of a commercial pre-starter diet: mashed, crumbled and pressed into pellets. Except for gizzard, the other organs of the digestive tract and morphologic structures of the small intestine were not affected by the physical form of the diet. The highest N digestibility was observed in birds fed pellet diet, while crumbled diet showed the highest digestibility of EE. The metabolizable energy determined for mashed diet was lower than those determined for the other physical forms of the diet. Birds fed mashed diet had the lowest feed intake and body weight gain and the worse feed conversion. These birds also showed lower intake of energy and less protein, fat and energy retention in the body. They used a higher proportion of the energy consumed for heat production. Pre-starter diets prepared as pellets or crumbles allow better nutrient utilization and improve chick performance.

Effect of Thermal Processing, Press Throughput and Roller-Die Gap on Physicochemical Properties of Broiler Feed Pellets

The present study aimed to evaluate the effect of thermal processing, press throughput and roller-die gap on pellet physical quality, protein solubility and starch gelatinization in a corn-soybean based broiler diet. The different processing factors were combined in a 2 × 5 × 3 factorial arrangement with eight randomized block consisting of eight production series: two thermal processing treatments (conditioning-pelleting or conditioning-expanding-pelleting), five press throughput levels (18, 21, 24, 27 and 30 ton/h) and three roller-die gap (0.50, 0.75 and 1.00 mm), which resulted in 30 different processed feeds. For determination of pellet durability index (PDI), amount of intact pellets, degree of starch gelatinization and protein solubility, one composed feed sample was collected per treatment in each of eight production series, totaling eight replicates per treatment. Data concerning the amount of intact pellet and protein solubility in KOH were transformed using a variation of Box-Cox transformation in order to fit a normal distribution (P > 0.05). Pellet physical quality was enhanced by conditioning-expanding treatment (P < 0.01), narrower roller-die-gap (P < 0.01) and reduced press throughput (P < 0.01). Protein solubility in KOH was impaired (P < 0.01) in the expander treatment and larger roller-die distance (0.75 mm and 1.00 mm) (P < 0.01). Finally, greater starch gelatinization degree was achieved in expanded treatment (P < 0.01) and in 1.00 mm roller-die gap (P < 0.05). The factors evaluated in this study resulted in interactions and significant effects on physicochemical properties of broiler feed pellets.

Factors that Affect Pellet Quality: A Review

Pelleting is the most popular thermal processing technique in poultry industry. Birds fed pelleted diets have greater feed intake and weight gain, and better feed conversion ratio. However, this better performance can only be achieved, if the pellets remain intact until they are ingested by the birds. Many factors may affect pellet physical quality, such as feed nutritional composition, ingredient particle size, conditioning temperature and time, feed moisture, etc.. Despite their importance, sometimes these factors are not managed properly, therefore, pelleted feed may not contain a high amount of intact pellets. In addition, the possible interactions among these variables may yield different responses in comparison with those expected when individual factors are considered. Very few experiments have been conducted to evaluate the impact of combined factors on pellet quality. This may be explained by the presence of many qualitative and quantitative factors in the manufacturing process. Research indicates that heat processing and feed formulation, especially fat inclusion level, are the factors which have the biggest influence on pellet quality. Strategies, such as the expansion process and fat inclusion restriction or post pellet liquid fat application could be implemented to produce high physical quality pellets. More research is needed to identify which factors have a positive or negative effect on pelleting process and to find new strategies to improve pellet physical quality.

Impact of Particle Size, Thermal Processing, Fat Inclusion, and Moisture Addition on Starch Gelatinization of Broiler Feeds

The present study evaluated the effect of feed particle size, thermal processing different levels of fat inclusion and of moisture addition on the amount of gelatinized starch in a corn-soybean broiler diet. The different processing factors were combined in a 2 x 4 x 4 x 2 factorial arrangement in a three randomized block design consisting of three production series: two particle sizes (coarse: 1041 microns and medium: 743 microns), four fat inclusion levels at the mixer (15, 25, 35, and 45 g/ kg of feed), four moisture addition levels in the conditioner (0, 7, 14, and 21g/kg of feed), and two thermal processing treatments (conditioningpelleting or conditioning-expanding-pelleting) which resulted in 64 different processed feeds. For the determination of the amount of gelatinized starch one feed sample was collected per treatment in each of three production series, totaling three replicates/treatment. Data were transformed using a variation of Box-Cox transformation in order to fit normal distribution (p>0.05). Adding moisture up to 21g/kg of feed in the conditioner linearly increased the amount of gelatinized starch (p<0.05). The conditioner-expander-pelleting treatment of the diets (at 110°C) increased (p<0.05) the degree of starch gelatinization from 32.0 to 35.3 % compared with the conditioner-pelleting treatment (at 8082°C). The gelatinized starch content increased from 30.2 to 37.2% in the feed (p<0.05) as the particle size increased from medium to coarse. Fat inclusion had a quadratic effect (p<0.05) on starch gelatinization. The degree of starch gelatinization was significantly reduced with fat inclusion levels higher than 35 g/kg of diet. The factors evaluated in this study resulted in interactions and significant effects on degree of starch gelatinization.

Efeitos de Produto de Exclusão Competitiva na Prevenção dos Efeitos Tóxicos da Ocratoxina A em Frangos

This experiment aimed at evaluating the action of competitive exclusion (CE) on the effects of ochratoxin A (OA). Birds fed 2ppm OA in the diet had significant lower feed intake, weight gain, and feed conversion than birds not exposed to OA in the diet. The use of CE on the first day of age did not minimize these effects nor the performance parameters studied. Birds fed OA has lower vaccinal titers of Newcastle disease virus, showing the interference of this mycotoxin on the humoral immune response of broilers. CE did not interfere in the humoral immune response of broilers vaccinated for Newcastle disease. OA and CE did not influence villus height, crypt depth, nor villus:crypt ratio in seven-day-old birds as compared to control broilers of the same age.