The study aimed to assess the effect of different dietary levels of a probiotic blend (Probio Enzyme®) during the first 14 days of age (DOA) or up to 42 DOA, on growth performance, carcass and digestive tract traits, and haematological profiles of broiler chicks. A total of 540, one-day-old broiler chicks were randomized assigned to nine treatments: four dietary probiotic blend levels (250, 500, 750, and 1,000 g/ton) within two feeding periods (0-14 and 0-42 d, respectively), whereas the ninth treatment was a control diet without any dietary probiotic supplementation. The feed intake (FI) was found to be higher in broilers fed 1,000 g/ton of probiotic blend when fed during the first 14 d; however, BW gain and feed efficiency were not influenced by the treatments. Carcasses (deplumed and full) from broilers fed 250 g/ton of probiotic blend (0-14 DOA) were heavier than the other groups; the same was observed for leg portions. Broiler duodenum, jejunum and ileum weights, and ileum percentage were greater when fed diets without any supplementation. The haematological profile of broilers was not affected by the dietary treatments.

RESUMO: O objetivo do presente trabalho foi avaliar os efeitos da suplementação com solução de sulfato de cobre (SSC) e arginina em pó (Arg) sobre o desempenho, hormônios tireoidianos e bioquímica sanguínea de frangos de corte alimentados com dietas à base de canola DC. O desenho experimental foi completamente casualizado com fatorial 3 × 3 e nove tratamentos correspondentes a três níveis de inclusão de SSC (0, 125 e 250 mg/kg) e três níveis de Arg (0, 0,1 e 0,2%) (n = 45 para cada tratamento). As rações foram oferecidas ad libitum por 21 dias, de 22 até 42 dias de idade. A eficiência alimentar foi significativamente afetada pela adição de 250 mg/kg de SSC e 0,2% de Arg, assim como pela interação SSC × Arg. A suplementação da DC com SSC melhorou os parâmetros da glândula tireoide e aumentou os níveis plasmáticos de triiodotironina e tiroxina. As aves alimentadas com dietas suplementadas com 0,2% de Arg apresentaram menor nível de glicose sanguínea do que as dos demais tratamentos. A adição de 250 mg/kg de SSC e 0,2% de Arg reduz o estresse causado pelo rápido crescimento dos frangos, além de melhorar as condições gerais de bem estar das aves.

ABSTRACT: The present evaluated the effects of copper sulfate solution (CSS) and arginine powder (Arg) supplements on performance, thyroid hormones and blood biochemistry of broiler chickens fed with canola meal (CM)-based diets. The experimental design was completely randomized with a 3 × 3 factorial and 9 treatments, corresponding to 3 levels of CSS (0, 125 and 250 mg/kg) and 3 levels of Arg (0, 0.1 and 0.2%) (n = 45 per treatment). Feeds were offered ad libitum for 21 days, from 22 to 42 days of age. Feed efficiency was significantly affected by the dietary addition of 250 mg/kg CSS and 0.2% Arg, and by the CSS × Arg interaction. CM supplemented with CSS improved the thyroid gland status and increased the plasma levels of triiodothyronine and thyroxine. Birds fed diets supplemented with 0.2% Arg had lower blood glucose level than the other treatments. The addition of 250 mg/kg CSS and 0.2% Arg reduced the stress caused by the rapid growth of broilers, also increasing the overall bird welfare.

Resumen Antecedentes: El uso de programas de restricción alimenticia temprana en pollos de engorde puede prevenir el incremento de la deposición de grasa corporal y sus consecuencias. Sin embargo, la restricción alimenticia no proporciona siempre los resultados esperados. Objetivo: Investigar los efectos de dos niveles de restricción alimenticia seguida por un período de realimentación con cinco niveles crecientes de nutrientes sobre el rendimiento productivo y la respuesta inmune de pollos de engorde. Métodos: Se utilizaron 330 animales. Los tratamientos fueron: restricción cuantitativa del 25 (T25) y del 35% (T35) durante el periodo de iniciación y aumento de la energía y contenido proteico de la dieta del 0, 2,5, 5, 7,5, 10 y 15% durante los periodos de crecimiento y finalización. Resultados: Para casi todos los T25 el consumo de alimento (FI) y el aumento de peso corporal (BWG) fueron mayores y el índice de conversión (FCR) menor (p<0,05) en comparación con el control. La respuesta del FI y el BWG al aumento de la densidad de nutrientes en este grupo fue mayoritariamente cuadrática (p<0,001), mientras que en el caso del FCR fue lineal (p<0,001). Los resultados del FI y el BWG fueron menos homogéneos en los T35, pero el FCR fue menor que en el control (p<0,05). El FCR no mostró diferencias (p>0,05) entre tratamientos durante el periodo de acabado. Conclusión: La alimentación con una dieta rica en nutrientes después una restricción ligera proporciona los mejores resultados, mientras que el incremento de la densidad de la dieta después de una restricción severa no mejora los resultados productivos en comparación con una dieta estándar. Las características de la canal y la respuesta inmune no se vieron afectadas por el nivel de restricción o la densidad de nutrientes de la dieta.

Resumo Antecedentes: O uso de programas de restrição precoce de nutrientes em frangos de corte tem o potencial de prevenir complicações como o aumento da deposição de gordura corporal e suas consequências. No entanto, a restrição alimentar nem sempre dá os resultados esperados. Objetivo: Investigar os efeitos de dois níveis de restrição alimentar seguidos de um período de re-alimentação com cinco níveis crescentes de nutrientes no rendimento produtivo e na resposta imune de frangos de corte. Métodos: Foram utilizados 330 animais. Os tratamentos foram: restrição quantitativa de 25 (T25) e 35% (T35) durante o período inicial e aumento do conteúdo energético e proteico da dieta de 0, 2,5, 5, 7,5, 10 e 15% durante os períodos de crescimento e finalização. Resultados: Para todos os tratamentos T25, menos para T25-0, consumo de ração (FI) e ganho de peso corporal (BWG) foram maiores e a taxa de conversão (FCR) foi menor (p<0,05) o controle. A resposta do FI e do BWG ao aumento da densidade de nutrientes nesse grupo foi principalmente quadrática (p<0,001), enquanto no caso da FCR foi linear (p<0,001). Os resultados do FI e do BWG foram menos homogêneos nos tratamentos T35, mas o FCR foi menor que no tratamento controle (p<0,05). O FCR não apresentou diferenças (p>0,05) entre os tratamentos durante o período de terminação. Nenhuma tendência clara foi observada no peso relativo dos órgãos linfóides ou na resposta imune devido aos tratamentos testados. Conclusão: A alimentação de uma dieta rica em nutrientes após um período de restrição leve proporcionou os melhores resultados, enquanto o aumento da densidade de nutrientes na dieta após uma restrição severa não melhorou os resultados produtivos em comparação com uma dieta padrão.

Abstract Background: The use of early nutrient-restriction programs in broilers can prevent complications such as increased body fat deposition and its consequences. However, feed restriction not always gives the expected results. Objective: To assess the effect of two levels of feed restriction followed by a re-alimentation period with five increasing nutrient levels on growth performance and immune response of broiler chickens. Methods: A total of 330 animals were used. The treatments were: 25 (T25) and 35% (T35) quantitative feed restriction during the starting period, and 0, 2.5, 5, 7.5, 10, and 15% increased energy and protein contents during the growing and finishing periods. Results: For all the T25 treatments, except for T25-0, feed intake (FI) and body weight gain (BWG) were higher, and feed conversion rate (FCR) was lower (p<0.05) compared to the control treatment. In that group, the response of FI and BWG to the increased nutrient density was mostly quadratic (p<0.001), whereas that of FCR was linear (p<0.001). The FI and BWG results were less homogeneous in the T35 treatments, but FCR was lower compared to the control treatment (p<0.05) in all of them. The FCR showed no differences (p>0.05) between treatments during the finishing period. Conclusion: Feeding a nutrient-dense diet after a period of mild feed restriction gives the best results, while increasing nutrient density after a more severe feed restriction does not improve productive results compared to a standard diet. Carcass traits and immune function were not affected by restriction level or nutrient density.

ABSTRACT The effects of vitamins E and C supplementation on growth performance and biochemical and haematological parameters of Japanese quail were studied. A total of 360 one-day-old Japanese female quails were randomly allocated to nine dietary treatment groups (10 birds per replicate and 4 replicates per treatment), including a control (basal diet) and the basal diet supplemented with: 250 or 500 mg/kg of vitamin C, 250 or 500 mg/kg of vitamin E, 250 mg/kg of both vitamins E and C, 250 and 500 mg/kg of vitamins E and C, 500 and 250 mg/kg of vitamins E and C, and 500 mg/kg of both vitamins E and C. Vitamin supplementation improved productive parameters and raised the blood plasma levels of protein, thyroid-stimulating hormone, calcium and phosphorus, while decreased those of glucose, uric acid, creatinine and triglycerides, as well as lowered the activities of aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase. Leukocyte count as well as the heterophil to lymphocyte ratio decreased and red blood cell count increased in the supplemented groups. The results obtained support that the simultaneous supplementation with vitamins E and C has greater positive effects on growth performance, metabolism indicators and haematological parameters than their supplementation separately, which in turn shows improvements over the absence of supplementation.

A factorial experiment was conducted to investigate the effects of L-Carnitine and fenofibrate on broilers. There were four replicates of four treatments, with each replicate including ten male Ross 308 broiler chickens. The experiment was conducted over a 42-day period. The treatments consisted of two levels of L-Carnitine (200 and 400 mg/kg) and two levels of fenofibrate (50 and 100 mg/kg) as supplements to a basal diet. Growth, carcass characteristics, serum constituents, immune system responsiveness, cecal microflora, sensory attributes and fatty acid profiles of breast meat, and small intestine histology were characterized. During the finishing period, the chickens fed a diet containing 400 mg/kg L-Carnitine and 50 or 100 mg/kg fenofibrate had lower feed intake andfeed conversion ratio (FCR) and higher weight than the other treatments. Application of 400 mg/kg L-Carnitine in combination with two levels of fenofibrate reduced ventricular fat (P <0.05), cholesterol (P <0.01), triglycerides (P <0.05), and very low density lipoprotein (VLDL) (P <0.05). These treatments increased antibody titers against Newcastle disease (ND)and avian influenza virus (AIV). Among the sensory properties of breast meat, experimental treatments had a significant effect only on its aroma (P <0.05). In general, supplementing the diet of Ross 308 broilers with 400 mg/kg L-Carnitine and 50 or 100 mg/kg of fenofibrate is recommended.

A total of 192 one-day-old Ross 308 chicks were weighed individually (42.0 ± 0.8 g live weight) and randomly assigned to four dietary groups, each with three replicates of 16 birds. One group was a control (CON) and fed a starter diet without supplementation. The other three groups were fed the same starter diet during the starter phase (1 - 10 days old) supplemented with lecithin (LEC) at 0.05 g/kg diet or lipase (LIP) at 0.05 g/kg, or a combination (LEC+LIP) at 0.05 + 0.05 g/kg. No significant effects of supplementation with LEC and LIP on feed intake of broilers were observed during the starter phase, whereas bodyweight gain increased after the combined addition of these supplemental ingredients. Thus, final bodyweight was greater in LEC+LIP broilers compared with the other groups. Dietary supplementation with LEC or LIP had a positive effect on final bodyweight. However, the effect was less than the simultaneous supplementation of LEC+LIP. Moreover, the feed conversion ratio in the LEC+LIP group improved (P <0.05) in the finisher phase (25 - 42 days old). Carcass traits and blood parameters were not influenced significantly by treatments, whereas supplementing LEC+LIP stimulated the immune system of broilers significantly. Thus, it can be concluded that supplementing LEC and LIP in early-stage broilers supported their performance and immune response positively up to finisher rearing phase.

Resumo O objetivo deste trabalho foi avaliar o efeito de farinha de minhoca (EW) (Eisenia fetida) dietética, associada ao vermi-húmus (VH), sobre o desempenho, as características dos ovos, a imunidade e os constituintes do sangue de codornas poedeiras. Um total de 336 codornas fêmeas (42,5±1,5 g), com 30 dias de idade, foi distribuído em 7 tratamentos e 4 repetições de 12 aves, por 42 dias. Foram avaliados os seguintes tratamentos: dieta controle sem a inclusão de VH e EW; dieta com inclusão somente de 0,8% VH; e dieta com 0,8% VH suplementada com diferentes níveis de EW (0,5, 1,0, 1,5, 2,0 e 2,5%). Foram obtidos maiores peso vivo, ganho de peso e consumo de ração com 1,5% de EW; maior produção de ovos com 0,5–1,0% de EW; e maior massa de ovos com 0,5% de EW. A inclusão de 2,5% EW reduziu o peso e a espessura da casca do ovo. Níveis de 1,0–2,0% de EW diminuíram o malonaldeído nos ovos, enquanto o de 2,0% de EW reduziu o conteúdo de colesterol. Foram obtidos maiores volume de células sanguíneas e título de anticorpos com 1,0% de EW, enquanto maiores proteína total, globulina e cálcio foram obtidos com 0,5% de EW. Níveis de 1,0–1,5% + 0,8% de VH melhoram a produção e as características dos ovos, bem como a resposta humoral das codornas, cujo desempenho não é afetado.

Abstract The objective of this work was to evaluate the effect of dietary earthworm (Eisenia fetida) meal (EW), associated with vermi-humus (VH), on the performance, egg characteristics, immunity, and blood constituents of laying quails. A total of 336 female quails (42.5±1.5 g), with 30 days of age, was distributed in 7 treatments and 4 replicates of 12 birds during 42 days. The following treatments were evaluated: control diet without the inclusion of VH and EW; diet with the inclusion of only 0.8% VH; and diets with 0.8% VH supplemented with different EW levels (0.5, 1.0, 1.5, 2.0, and 2.5%). A greater body weight, weight gain, and feed intake were obtained with 1.5% EW; a higher egg productivity, with 0.5–1.0% EW; and a higher egg mass, with 0.5% EW. The inclusion of 2.5% EW reduced eggshell weight and thickness. Levels of 1.0–2.0% EW decreased malondialdehyde in the eggs, whereas 2.0% EW reduced cholesterol content. Higher blood cell volume and antibody titer were obtained with 1.0% EW, whereas higher total protein, globulin, and calcium were obtained with 0.5% EW. Levels of 1.0–1.5% EW + 0.8% VH improve egg production and characteristics, as well as the humoral response of quails, whose performance is not affected.

RESUMO A produtividade e a qualidade da carne bovina são determinadas por diversos fatores, incluindo características de pedigree dos animais. A produtividade da carne tem relação íntima com os padrões biológicos de seu crescimento e desenvolvimento. A consideração dos padrões que afetam a produtividade da carne possibilita o crescimento e engorda eficazes dos rebanhos e a obtenção de carne bovina comercialmente viável. Para prever características economicamente úteis na criação de gado de corte, indicadores de interior podem ser usados, visto que refletem a imagem metabólica do corpo do animal. Tornam-se relevantes os estudos de pesquisa em fisiologia e bioquímica da pecuária com o objetivo de revelar os mecanismos persistentes de um organismo animal em crescimento. O artigo identifica uma correlação entre os indicadores internos e os indicadores de engorda de três grupos experimentais de novilhos. Os principais fatores de previsão dos indicadores de produtividade de carnes já foram comprovados. Coeficientes de regressão foram encontrados e mostram o quanto o peso vivo varia em função dos fatores determinantes. Os procedimentos de predição da produtividade da carne foram modelados em relação ao conteúdo de proteína no soro sanguíneo.

ABSTRACT Meat productivity and quality of beef are determined by a number of factors, including pedigree traits of animals. Meat productivity is closely related to the biological patterns of their growth and development. Considering the patterns that affect meat productivity enables effective growing and fattening of livestock and obtaining commercially viable beef. To predict economically useful traits in beef cattle breeding, interior indicators can be used, as they reflect the metabolic picture of the animal’s body. The research studies in physiology and biochemistry of livestock aimed at revealing the persistent mechanisms of a growing animal organism make them relevant. The article identifies a correlation between the interior indicators and the fattening indicators of three experimental groups of steers. The main forecasting factors of meat productivity indicators have been substantiated. Regression coefficients have been found and show how much the live weight varies depending on the determining factors. Meat productivity predicting procedures have been modeled with respect to the protein content in blood serum.

ABSTRACT The present study was carried out to determine the effect of tilapia Oreochromis niloticus on the physical and chemical sediment parameters on an earthen pond in monoculture (shrimp Penaeus vannamei) and co-culture (tilapia-shrimp) during the dry and wet seasons in a commercial farm during the period from mid-September to end-December 2017 and February to mid-May 2018. Chemical and physical analyses were realized on sediment samples from brackish water ponds representing shrimp farms in San Blas Nayarit, Mexico. Concentrations of organic carbon, nitrogen, potassium, magnesium and calcium were higher in co-culture ponds, and there was a tendency to a higher concentration of phosphorus and sodium in the sediment of monoculture ponds. The texture of the ponds showed a tendency in the dry season to increase the percentage of clay in co-culture due to the effect of bioturbation caused by tilapia. There was no evidence of poor development of sediment quality in any treatment. It was found that tilapia was a factor that affected sediment quality, differences in growth between shrimp monoculture and tilapia-shrimp co-culture can be explained, at least in part, by differences in their sediment.

ABSTRACT This experiment was conducted to evaluate the effects of stocking density and climate region on performance, immunity, carcass characteristics, blood plasma, and economic parameters of the Ross strain of broiler chickens. The effects of four climates (mild and humid, semi-arid, alpine, and hot and dry) and four densities (10, 15, 17, and 20 chicks/m2) were studied as a completely randomized design with 4×4 factorial arrangement of treatments. The results showed that the density had a significant effect on feed intake and feed conversion ratio in the starter period and on body weight gain in the grower and the whole periods of the experiment. Moreover, both climate and density had a significant impact on economic performance (live weight, survival rate, production index, meat production/m2, and profitability). The mild and humid climate and the density of 17 chicks/m2 had the most economic benefit compared with other treatments. The climate type had a significant effect on the relative weights of the breast, wings, neck, proventriculus, and ileum. The effects of climate and density on glucose, triglyceride, very low-density lipoproteins (VLDL), high-density lipoproteins (HDL), LDL/low-density lipoproteins (HDL), total protein and globulin were significant. In addition, the effect of climate on the antibody titer against sheep red blood cells (except for immunoglobulin G on day 28) was significant.

ABSTRACT An experiment was conducted based on a completely randomized design with 500 Ross 308 broiler chickens to investigate the effect of three different sources of selenium on performance and characteristics of immune system. Chickens were arranged in 10 treatments and five repetitions (10 chickens for each repetition). Ten treatments of experimental diet were considered in the study, including a basal diet (control); 0.5, 0.8, and 1.2 mg nano-selenium + basal diet (three treatments); 0.5, 0.8, 1.2 mg selenomethionine + basal diet; and 65, 80, and 100 mg vitamin E + selenium + basal diet. Findings suggested that adding selenomethionine (1.2 mg) to the basal diet resulted in a significant effect on feed conversion ratio and weight of broilers. In fact, weight and bursa of Fabricius were significantly under influence of the diets containing nano-selenium. Moreover, a significant difference was observed in the antibodies produced against Newcastle and influenza as well as the total immunoglobin and IgG produced against sheep red blood cell at two stages in the group treated with nanoselenium. Finally, results indicated that nano-selenium can better improve performance and immune system of broilers compared with diets containing selenomethionine and vitamin E.

Resumen Antecedentes: la rotura de la cáscara es un problema que afecta a los huevos para incubación, reduciendo la eficiencia económica de la producción. Objetivo: determinar la eficacia del sellado de micro grietas de huevos utilizando parafina fundida, esmalte de uñas transparente, o esmalte de color sobre la incubabilidad, mortalidad embrionaria (EM) y peso de los pollitos (CW). Métodos: los huevos (n= 576) con micro fisuras fueron asignados a uno de cuatro grupos durante un período de incubación de 21 días. Un grupo se mantuvo sin tratar (CE), en los otros grupos se selló el área micro-agrietada de la cascara con esmalte incoloro de uñas (NV), esmalte de color (CV), o parafina fundida (MP). Tambien se incluyó un grupo de huevos no agrietados (UE, n= 144). Resultados: los tres tratamientos aplicados a la cascara permitieron obtener una pérdida de peso normal de los huevos a 18 d (11,45%), asi como un peso normal de los pollitos (44,7 g). El grupo NV presentó incubabilidad y EM similares a UE durante el periodo de incubación (84,02 vs 86,11% incubalidad y 6,95 vs 10,42% EM entre los días 1-10; y 2,08 vs 1,39% EM entre los días 18-21 respectivamente; p>0,05). El grupo CV tuvo incubabilidad inferior a la de NV (77,77 vs 84,02% respectivamente; p<0,05), mientras que el grupo MP mostró incubabilidad similar a la obtenida por el grupo CE (59,72 vs 72,92%, respectivamente p>0,05). Conclusiones: la aplicación de esmalte incoloro de uñas en las micro-grietas de la cascara mejora la incubabilidad de los huevos.

Abstract Background: Shell fragility of hatching eggs can have negative implications on the economic performance of hatcheries. Objective: To determine the efficacy of sealing eggshell micro cracks with either coloured or uncoloured nail varnish, and molten paraffin on hatchability, embryonic mortality (EM) and hatched chick weight (CW). Methods: Eggs (n= 576) with micro-cracks were assigned among four groups (n=144 each group) for a 21 d incubation period. One group was untreated (CE). In the other groups, the micro cracked area of eggshells was sealed with uncolored nail varnish (NV), colored nail varnish (CV), or molten paraffin wax (MP). A positive control group of un-cracked eggs (UE) was also included (n= 144). Results: The eggshell sealant treatments allowed normal conductance related to egg weight loss after 18 d of incubation (11.45%), and chick weights were normal among treatment groups (44.7 g). Hatchability and embryonic mortality in the early and late incubation periods of the NV group was similar to UE (84.02 vs 86.11% for hatchability, 6.95 vs 10.42% for EM on days 1-10, and 2.08 vs 1.39% for EM on days 18-21 respectively; p>0.05). The CV group had lower hatchability than the NV (77.77 vs 84.02% respectively; p<0.05), whereas MP showed similar hatchability compared to the CE group (59.72 vs 72.92%, respectively p>0.05). Conclusions: Application of uncoloured nail varnish on shell micro-cracks improves egg hatchability.

Resumo Antecedentes: a quebra da casca do ovo é um dos problemas mais importantes durante a incubação, reduzindo a eficiência económica da produção. Objetivo: determinar a eficácia da selagem de microfissuras na casca de ovo com verniz de unhas, transparente ou colorido, e parafina fundida na eclosão, mortalidade embrionária (EM), e peso dos pintos ao nascimento (CW). Métodos: ovos (n= 576) apresentando microfissuras foram divididos em quatro grupos (n= 144) e colocados a incubar por um período de 21 dias. Um dos grupos não foi tratado (CE). Os ovos dos restantes grupos foram selados com verniz de unhas transparente (NV), verniz de unhas colorido (CV) ou parafina fundida (MP). Foi ainda incluido um controlo positivo constituído por ovos sem microfissuras (UE) (n= 144). Resultados: em todos os grupos tratados, observou-se uma perda de peso normal após 18 dias de incubação (11,45%) assim como um peso vivo normal dos pintos ao nascimento (44,7 g). Observou-se uma taxa de eclosão e mortalidade embrionária similar dos períodos iniciais e finais de incubação entre os grupos NV e UE (84,02 vs 86,11% para eclodibilidade, 6,95 vs 10,42% para EM entre os dias 1-10, e 2,08 vs 1,39% para EM entre os dias 18-21 respectivamente; p>0,05). O grupo CV evidenciou uma taxa de eclosão menor do que a do grupo NV (77,77 vs 84,02% respectivamente; p<0,05). No entanto, o grupo MP apresentou uma eclodibilidade similar à observada no grupo CE (59,72 vs 72,92%, respectivamente p>0,05). Conclusões: o uso de verniz de unhas transparente é um método apropriado para incrementar a eclodibilidade de ovos com microfissuras.

This study was designed to evaluate the effects of different sunflower meal (Helianthus annus; SFM) levels and a multi-enzyme complex (Natuzyme P50) on performance, biochemical parameters and antioxidant status of laying hens. A total of 288 Hy-Line W-36 laying hens (39-wk-old) were divided into six groups with six replicates per group (eight birds per replicate) and fed one of the six experimental diets. A corn-soybean meal-based diet was formulated and used as control diet. The experimental treatments consisted of three levels of SFM (0, 10, and 20%) and two levels of multi-enzyme complex (0 and 250g/ton). The feeding trial lasted 10 weeks. The results showed that the egg production, egg weight and mass, egg specific gravity, shell strength and thickness, Haugh unit, shape index, triglyceride content, plasma glutathione peroxidase (GSH) activity, and malondialdehyde (MDA) were not influenced by dietary treatments; however, the feed consumption, yolk cholesterol, low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol were significantly affected by feeding SFM compared to the control. In conclusion, the supplementation of SFM up to 20% in diet with multi-enzyme complex in laying hens did not appear to cause any adverse effects on egg production and quality as well on antioxidant status in laying hens.

This experiment was conducted to investigate the effects of various levels of organic acids and virginiamycin on performance, blood parameters, immunoglobulin and microbial population of broiler chickens. This trial was conducted in a completely randomized design using five treatments and four replicates. The dietary treatments included a control diet without additives, diets containing 0.05%, 0.10% and 0.15% mixtures of organic acids, and a diet containing virginiamycin as an antibiotic. Based on the results, there was no significant effect of the experimental diets on feed intake of the broilers during the starter period. However, at the end of the grower period and throughout the rearing period, feed intake was significantly improved by experimental dietary treatments. Moreover, diets including organic acids enhanced the microbial population of broiler gut. Thus, the current findings support the conclusion that organic acids improve productive traits and health status in broiler chickens.

ABSTRACT The objective of this study was to analyze the effect of environmental factors on egg production curve traits in broiler breeders. The weekly egg production records of birds collected from four different flocks were used to estimate the egg production curve parameters using the Compartmental function (y = A(1 − exp−b(t − d))exp−ct). The coefficient of determination (R2) obtained by the model was 0.98. Least squares analysis of variance indicated that the environmental factors such as hatchability and flock had significant effects on egg production curve traits. The highest correlation was observed between the weekly potential maximum yield and yield at the beginning of laying, whereas the lowest correlation was found between the weekly potential maximum production and production after peak yield. Associated factors with the increasing slope of egg production curves had a negative correlation with the decrease after peak. The correlation analysis showed that peak production had a negative and significant relationship with production towards peak and time to reach peak production, while there was a positive and significant correlation with the slope decrease after peak yield. The Compartmental function can be used as an alternative model to predict egg production traits in broiler breeders.