Am Penz

Different sodium levels and electrolyte balances in pre-starter diets for broilers

An experiment with 400 one-day-old male chicks (Ross) was conducted to evaluate the effects of different Na levels (0.10, 0.22, 0.34 and 0.46%) and different cation/anion balances (Na+K-Cl) (100, 150, 200, 250 and 300 meq/kg) in pre-starter diets on broiler performance. The corn and soybean-based diets had 22% crude protein and 2,900 kcal/kg metabolizable energy and were fed ad libitum. Performance data showed a positive quadratic effect of increasing Na levels on feed and water consumption, weight gain and feed conversion. Na+K-Cl also had a quadratic influence on feed intake and weight gain. None of the effects tested affected the amount of water measured in excreta. Derivatives of obtained regression equations pointed to optimal Na levels of 0.45% for water consumption, 0.40% for feed intake and weight gain and 0.38% for feed conversion. As to the effect of dietary Na+K-Cl balances on performance, regression equation values were 174 meq/kg for feed consumption and 163 meq/kg for weight gain. These results show that both Na level and Na+K-Cl balance interfere on broiler performance.

Efeito da Energia, Relação Energia: Proteína e Fase de Crescimento Sobre o Desempenho e Composição de Carcaça de Frangos de Corte

Two experiments (EXP) were carried out to investigate the effects of crude protein (CP) levels reduction in high-energy (H) (3.200kcal ME/kg) and low-energy (L) (2.900kcal ME/kg) diets, on the performance and carcass composition of male broiler chickens. The CP levels were decreased to meet the following energy: protein (E:PB) ratios: 139, 146, 153 and 160 (kcal/%) for starter diets (EXP 1) and 160, 167, 174 and 181 (kcal/%) for grower diets (EXP 2), in both energy levels, keeping MET + CIS and LYS levels at the same concentration. All birds received a same diet before (EXP 2) or after (EXP 1) feeding the experimental diets. Feeding H diets resulted in better performance, but also in higher carcass fat deposition. In EXP 1, birds fed with L diets during the starter period had similar body weight gain (BWG), in the total period (1 to 42 days), than those H diets, however with better caloric conversion (kcal/kg) (CC). Also, the best CC was obtained with E:PB of 139. Lower BWG, sometimes occurred with lower levels of dietary CP, but in all experiments the CC was decreased with wider E:PB ration. In both EXP, protein utilization was improved with higher levels of dietary energy and with lower levels of dietary CP.

Effect of energy levels of diets formulated on total or digestible amino acid basis on broiler performance

This study was conducted to evaluate the performance and carcass and breast yields of broilers fed two different energy levels (3,200 or 2,900 kcal ME/kg) and two ways of expressing amino acid requirements (total n TAA or digestible n DAA) between 21 and 42 days of age. The results showed that broilers fed the diet containing 3,200 kcal ME/kg had higher weight gain (P=0.015), better feed conversion (P=0.001), and higher abdominal fat deposition (P=0.001) as compared to those fed the diet containing 2,900 kcal ME/kg. Diets formulated on DAA basis promoted higher weight gain (P=0.043), better feed conversion (P=0.010) and better conversion of ME intake into weight gain (P=0.007) as compared to those formulated on TAA basis. The results of this study suggest that formulation based on DAA is necessary if the diets contain protein sources that are not reliable in terms of amino acid digestibility. The response to formulation based on DAA was minimized when birds received the low energy level diet (2,900 kcal ME/kg).

Granulometria do Milho em Rações de Crescimento de Frangos de Corte e seu Efeito no Desempenho e Metabolismo

Two experiments were carried out to evaluate corn particle size, expressed by the average geometric diameter (AGD), .0.337; 0.574; 0.680; 0.778; 0.868 e 0.936mm on performance, energetic metabolism and intestinal morphology (villi height and crypts depth of duodenum) of 21 to 42 day-old male broilers. In the first experiment, particle size of 0.868 mm showed greater feed intake and weight gain and better feed conversion. Villi height was not affected by the AGD of the diets, but increased with the broilers age (21, 35 and 42 days of age). Abdominal fat deposition was not affected neither the proportion of carcass cuts. Gizzard weight was positively related with particle size. In the second experiment, feed with particle size of 0.337 mm led to a lower energy intake and greater gross energy excretion. Nitrogen retention was not affected by particle size.

Diets formulated on total or digestible amino acid basis with different energy levels and physical form on broiler performance

We studied the effects of two different systems of expressing amino acid requirements (total - TAA or digestible - DAA), two energy levels (2,900 or 3,200 kcal of ME/kg) and two physical forms (mash or pellet) on the performance of male broilers from 21 to 42 d of age. Diets formulated on DAA basis improved feed conversion (p<0.001) and the conversion of consumed ME into body weight gain (p<0.001). Birds fed 3,200 kcal ME/kg presented better feed conversion (p<0.001), higher abdominal fat deposition (p<0.001) and worse conversion of consumed ME into body weight gain (p<0.001) as compared to birds fed 2,900 kcal ME/kg. Birds fed pelleted feed had higher feed intake (p<0.001), higher weight gain (p<0.001), better feed conversion (p<0.001), better conversion of consumed ME into body weight gain (p<0.001) and higher abdominal fat deposition (p<0.001). The results obtained in the present study suggest that feed formulation based on DAA is required when diets contain protein sources which amino acid digestibility is unreliable. Besides, pelleted feed improves performance parameters of broilers.

Fatty-acid composition of free-choice starter broiler diets.

Two experiments were carried out to evaluate the inclusion of vegetable oils with different fatty acid content in starter and pre-starter broiler diets. In Experiment I 480 1- to 9-day-old male Ross 308 broilers were fed diets containing corn oil (CO), acid corn oil (ACO), linseed oil (LO) or coconut fat (CoF). Chicks were distributed according to a factorial 2x2x2arrangement (2 free fatty acids - FFA ) x (2 n6:n3 ratios) x (2 medium-chain fatty acids levels - AGMC). Performance responses and dry matter (DMM), crude protein (CPM), and crude fat (CFM) metabolizability were evaluated. In Experiment II, 480 1- to 20-day-old male Ross 308 broilers were offered the free choice of 2 different diets: with no fat addition, or with 10% addition of the following fat sources: CO, LO, CoF, soybean soapstock (SBS), acid soybean oil (ASO), or acid cottonseed oil (ACtO). Performance responses and diet selection were evaluated. In experiment I, there were no significant effects of the diets on performance, DMM, or CPM; however, the inclusion of FFA depressed CFM. In experiment II, there was a marked preference of birds of the diets with fat inclusion, leading to the selection of diets with more than 3100 kcal/kg ME in the period of 1 to 20 days, independently of fat source. The broilers selected the high fat and energy diets since the first days of age, which resulted in better bird performance.

Suplementação de Treonina em Dietas de Frangos de Corte, Variando a Energia e as Relações Energia: Proteína

Dois experimentos (EXP 1 e 2) foram conduzidos para avaliar relacoes energia metabolizavel:proteina bruta (EM:PB) e a adicao de treonina (Thr) em dietas com alta (A) (3.200kcal EM/kg) e baixa (B) (2.900kcal EM/kg) energia, sobre desempenho e composicao de carcacas de frangos de corte machos. As relacoes energia:proteina foram 139 e 160 kcal/%, para as dietas iniciais (1 a 21 dias) (EXP 1) e 160 e 181kcal/%, para as de crescimento (22 a 40 dias) (EXP 2), nos dois niveis de energia. As dietas com ampla relacao EM:PB foram suplementadas, ou nao, com Thr a fim de iguala-las as dietas com menor EM:PB. Os niveis de Met+Cys e de Lys foram constantes. As aves receberam uma dieta unica apos (EXP1), ou antes (EXP2) do fornecimento das dietas experimentais. Nos dois EXP as dietas A proporcionaram melhor desempenho: ganho de peso (GP),consumo de racao e conversao alimentar (CA) (p<0,01), ao final de cada periodo experimental. Porem, no EXP 1, as aves que receberam dietas B tiveram melhor conversao calorica (CC, kcal/kg,) (p<0,01) no periodo total (1 a 40 dias), indicando um periodo de crescimento acelerado. Os niveis de Thr (0,74 e 0,69% para A e B respectivamente) das dietas com relacao EM:PB ampla nao foram limitantes no desempenho das aves. No EXP 2, a EM:PB 181 deprimiu o GP (p<0,08) e piorou a CA (p<0,01), nas energias A e B. Portanto, em dietas praticas iniciais, Thr nao foi um aminoacido (AA) limitante. Porem, de 22 a 40 dias, a adicao de Thr foi necessaria, em dietas com EM:PB 181kcal/%(EXP 2). A suplementacao de Thr nao influenciou a composicao das carcacas nos dois EXP.

Determination of apparent metabolizable energy of crude glycerin in broilers chickens.

The objective of the experiment was to determine the Apparent Metabolizable Energy corrected for nitrogen (AMEn) of a glycerin product derived from biodiesel production for broilers. A number of 35 male Ross 308 broilers, with 35 days of age was fed ad libitum diets containing 0, 5, 10, 15, or 20% glycerin. AMEn was determined using total excreta collection, with four days of adaptation and three days of collection. Increasing glycerin intakes resulted in increased water excretion. Glycerin AMEn varied as a function of dietary inclusion levels, and a cubic equation was identified by regression analysis. Maximum AMEn level- 4890 kcal/kg DM- was obtained with 15% glycerin inclusion. However, this level caused excessive water excretion, making its use unpractical.

Compensatory water consumption of broilers submitted to water restriction from 1 to 21 days of age

A hundred and fifty male Ross 308 broilers were submitted to water restriction (WR) in different levels (0 to 40%) until 21 days of age. The birds received water ad libitum from 22 to 28 days of age and the compensatory consumption of water (CConW) was calculated as the difference in water intake between birds submitted and not submitted to WR. All WR groups showed a compensatory consumption of water, mainly during the first days of the ad libitum period. The water intake in such groups decreased as the birds adapted to the new condition. Higher water intake was observed in birds with 30 and 40% WR than in birds with 10% WR. Furthermore, chickens showed an unusual drinking and feeding behavior during the restriction period.

Performance of female broiler breeders submitted to different feeding schedules

The performance of Arbor Acres broiler breeders (1,296 females; 144 roosters) was evaluated when submitted to the following treatments (T): T1 = feeding at 6:30 a.m. (control); T2 = 50% feeding at 6:30 a.m. and 50% at 3:30 p.m. (dual feeding); T3 = feeding at 11:00 a.m.; and T4 = feeding at 3:30 p.m. Treatments were randomly distributed in 48 pens. There were 27 females and 3 males in each pen and 12 repetitions per treatment. Nutrition and management were as recommended for the commercial strain. It was evaluated age at first egg (AFE), total egg production (TEP), number of days with production above 80% (DAP80), laying peak (P), female mortality (MOR), and gross profit margin (GM) per hen. Data were submitted to analysis of variance and means were compared by Students t-Test. TEP of T1 (186.3±2.3) and T2 (186.5±1.5) were higher (p 0.10) among treatments. GM per hen was better (p<0.05) in T1 and T2 hens. Control and dual treatments were more efficient than other treatments. It was concluded that it is possible to change conventional feeding managements by the dual feeding system.