Response of Laying Hens to Repletion and Depletion in Dietary Balanced Protein

This study was carried out to investigate the response of laying hens given a repletion or depletion in dietary balanced protein (BP) during the laying phase period. At the beginning of the rearing period (eight w-old), four-hundred pullets were equally distributed and received one of two experimental feeds: 1-Low BP (L) and 2-High BP (H). For the laying period (19 to 102 w-old), four feeding programs were designed based on the same treatments for rearing phases (LL, HH, LH, HL), where subsequent letters indicate the feed received during the rearing and laying period, respectively. The performance responses, egg quality, and body composition were periodically collected during the laying period. Two-way ANOVA repeated measures analysis was applied to evaluate the data. Nonlinear regression models with groups were used to compare treatments in the laying phase, with the treatments being the group evaluated. All performance traits were somehow influenced by the level of BP in the feed (p < 0.050). Hens subjected to the repletion treatment (LH) demonstrated a recovery in performance after 38 w-old. The opposite result was observed for hens on the depletion treatment (HL). All egg components were affected by dietary BP (p < 0.050). Laying hens demonstrated a limited capacity to overcome a reduction in dietary BP during production, but they were able to recover from a previous deficient feed once they were given an opportunity to do so.

Dynamics of Growth and Egg Traits in Three Dietary Balanced Protein Scenarios Applied for Laying Hens

Simple Summary

This study aimed to investigate the impact of three dietary balanced protein levels on laying hens, during the rearing and laying phases. The performance and body composition were monitored at 7, 11, 15, and 18 weeks old, while for the laying phase the responses were monitored every 28 days, from 19–102 weeks of age. The dietary protein applied in this study did not affect the responses evaluated in the rearing phase, but it clearly affected the long-term egg production. Overall, the egg production of hens consuming a high protein diet was superior compared to hens in the lower protein group and similar results were observed for body weight and body composition. The benefits of this study were to demonstrate the dynamic traits of laying hens in the long-term egg production cycle in three dietary balanced protein scenarios as similar data could not be found elsewhere.

Abstract

The objective of this study was to evaluate laying hens from 8 to 102 weeks old, regarding their changes in performance, body composition, and egg components produced in three scenarios of nutrition. Three treatments designed to contain different levels of balanced protein (BP) were randomly assigned to the experimental units, performing ten replicates per treatment with 20 birds each. A standard feed was formulated to meet hen requirements and the ideal ratio between essential amino acids. Then, two experimental feeds were formulated to contain 20% above or below the dietary BP used in the standard feed. The responses evaluated were cumulated feed intake (g), daily feed intake (g/day), body weight (g), body composition (g of protein, fat, and ash), hen-housed egg production (%/hen-housed), egg production (%), egg weight (g), egg mass (g), and egg components (percentages of yolk, albumen, and eggshell). The dietary BP influenced the body composition, egg production, egg weight, and egg mass of white laying hens. The increase in dietary BP was related to an increase in body contents and egg weight, whereas hens consuming the low dietary balanced protein presented a lower body weight, leaner, and produced smaller eggs.

Supplementation of minerals and vitamins in broiler diets: effect on performance and bone quality

Abstract Differences in growth rate and carcass composition of broilers may require higher levels of vitamins and minerals with higher bioavailability. The aim of this trial was to supplement commercial diets for broilers with optimized levels of vitamins and with different mineral sources to assess the effect on performance, carcass yield and bone quality. A total of 1,800 Cobb Slow male broiler chicks were distributed into a 2 x 2 factorial completely randomized design (vitamin programs - optimized and commercial versus mineral sources - inorganic [sulfates] and carbo-amino-phospho-chelate, CAPC). The vitamin D3 metabolite, 25 (OH) D3, was included in the optimized vitamin premix. Birds and feed leftovers were weekly weighed. Data was subjected to statistical analysis using the GLM procedure of SAS software. Supplementing diets with a combination of optimized vitamin programs and CAPC as mineral source resulted in better feed conversion at 42 days of age (P<0.05). Supplementation with CAPC minerals resulted in a lower red index (*a) (P<0.05) in the adjacent thigh muscles and drumstick bones of broilers when thawed and roasted, indicating less bone porosity. The inclusion rates of mineral sources with higher bioavailability can be reduced, decreasing the negative impact of mineral excretion and the polluting effect on the environment.

Bacillus subtilis and Bacillus licheniformis reduce faecal protein catabolites concentration and odour in dogs

BACKGROUND

Direct-fed microbials (DFM), such as Bacillus subtilis and Bacillus licheniformis, may improve gut functionality of the host by favouring non-pathogenic bacteria and reducing the formation of putrefactive compounds. The aim of this study was to assess the nutrient digestibility, faecal characteristics and intestinal-fermentation products in dogs fed diets with Bacillus subtilis and Bacillus licheniformis. Sixteen dogs were randomly divided into two groups. Every eight dogs were fed with the control diet or the diet with the addition of 62.5 g of DFM (B. subtilis and B. licheniformis)/ton. Diets were provided throughout a 20-day adaptation period, followed by 5 days of total faecal collection. Nutrient digestibility and the metabolisable energy of the diets, plus the dogs' faecal characteristics and intestinal fermentation products were assessed.

RESULTS

There were no differences in nutrient digestibility (P > 0.05). However, DFM supplementation improved faecal score and resulted in less fetid faeces (P < 0.001). DFM inclusion reduced (P < 0.05) the biogenic amines concentration: putrescine, spermidine and cadaverine, besides the concentration of phenols and quinoline.

CONCLUSIONS

The use of B. subtillis and B. licheniformis as DFM reduce the concentration of nitrogen fermentation products in faeces and faecal odour, but the digestibility of nutrients is not altered in dogs.

The dietary supplementation of canthaxanthin in combination with 25OHD3 results in reproductive, performance, and progeny quality gains in broiler breeders

The objective of this study was to evaluate the effects of the dietary supplementation of canthaxanthin and cholecalciferol (25OHD3) to broiler breeders and their progenies on their performance. Eighty 25-wk-old Cobb 500 broiler breeders were distributed according to a completely randomized design in 2 experimental treatments, with 10 replicates of 4 birds each. The treatments consisted of the supplementation or not of a corn-soybean meal diet with canthaxanthin + 25OHD3 to broiler breeders fed from 25 to 62 wk of age. Egg production, fertility, hatchability, hatchability of fertile eggs, embryonic mortality, and egg specific gravity were evaluated. Breeders were inseminated at 35, 45, and 62 wk of age, the eggs were incubated, and the performance of the progenies was evaluated. From the progeny of each breeder age, 300 male chicks were distributed according to a completely randomized design in a 2 × 2 factorial arrangement (chicks from breeders supplemented or not with canthaxanthin + 25OHD3 and chicks supplemented or not with canthaxanthin + 25OHD3), totaling 4 treatments with 5 replicates of 15 birds each. Canthaxanthin + 25OHD3 were supplied to the chicks until 21 D of age. The combination of canthaxanthin and 25OHD3, containing 69 mg of 25OHD3 and 6 g of canthaxanthin, was supplemented at 1 kg/t of feed. Breeders supplemented with canthaxanthin + 25OHD3 showed higher egg production, total hatchability, hatchability of fertile eggs, and lower early embryo mortality compared with those fed the control diet. Broilers from breeders fed canthaxanthin + 25OHD3 and supplemented with this additive up to 21 D of age presented a better feed conversion ratio and higher carcass and breast yields than those derived from nonsupplemented breeders.

Different dietary trace mineral sources for broiler breeders and their progenies

The objective of this study was to evaluate the effect of different trace mineral supplementation sources in the diet of broiler breeders on their performance and on their progenies. In total, 128 Cobb 500 broiler breeders were distributed according to a completely randomized experimental design in 2 experimental treatments. The control group was fed a diet supplemented with inorganic trace minerals (ITM), while the other group was fed a diet supplemented with reduced levels of trace minerals in the organic form. Eggs were collected when breeders were 35, 47, and 53 wk old. Their progeny (450 hatchlings) were divided according to trace mineral supplementation source from the maternal diet, creating 2 treatments with 16 replicates of 15 birds each. Organic trace mineral (OTM) supplementation improved broiler breeder performance, as shown by higher egg production and better eggshell quality of OTM-fed hens compared with those fed ITM. Egg fertility and hatchability were not influenced by the treatments. As to progeny performance, higher weight gain, and consequently, better feed conversion ratio, were obtained in the 41-day-old progenies of OTM-fed breeders, independently of hen age. Maternal diet trace mineral source did not affect broiler carcass, breast meat, or leg yields. The results of the present study show that supplementing broiler breeder diets with organic trace mineral sources enhances the performance of breeders and their progenies.

Efeito de diferentes densidades populacionais e do sexo sobre o desempenho e uniformidade em frangos de corte

O experimento teve a finalidade de comparar o desempenho e uniformidade de frangos de corte separados por sexo e criados em diferentes densidades populacionais. Para tanto foram utilizados 1800 pintos de 01 dia da linhagem Ross, distribuídos em 36 parcelas experimentais (Boxes), de acordo com um delineamento experimental tipo blocos ao acaso, obedecendo um modelo fatorial 3x2 com 3 sexos (Machos, Fêmeas e Misto) e duas densidades populacionais (10 e 15 aves/m²), com 6 repetições por tratamento, sendo 40 ou 60 aves por repetição. As rações experimentais foram formuladas à base de milho e farelo de soja. Foram efetuadas medidas semanais de consumo de ração e peso dos animais, e ao final de 45 dias os animais foram abatidos. Ao final do período experimental, os resultados mostraram que os maiores valores de peso, consumo, Conversão Alimentar e Ganho Médio Diário foram verificados na menor taxa de lotação empregada, havendo significância estatística (p<0,05) para os itens : consumo (todos os períodos) e Conversão Alimentar (1-21 e 22-45 dias). Todavia, o incremento na taxa de lotação apresentou maiores viabilidade e uniformidade.Quanto aos sexos empregados, foram observados melhores valores para os machos, havendo diferença significativa (p<0,05) para peso corporal (21 e 45 dias), consumo (22-45 e 1-45 dias), Conversão Alimentar (1-45 dias) e Ganho Médio Diário.

[Viral meningitis in the municipality of Rio de Janeiro, 1978]

Foram estudados 298 casos de meningites classificadas como virais ocorridos no 2º semestre de 1978 no município do Rio de Janeiro (Brasil). A maioria destes casos ocorreu de setembro a dezembro e pertenceu a um surto epidêmico causado pelo vírus ECHO-9. São apresentadas e discutidas as características epidemiológicas, clínicas e laboratoriais dos casos, bem como foi realizado um estudo caso-controle com parte dos casos do surto.

[Viral and bacterial meningitis in the municipality of Rio de Janeiro (Brazil). Some considerations on the health information system and the transmission of the disease in an urban area]

Foram estudados 609 casos de meningites ocorridos entre 1º de julho e 31 de dezembro de 1978 no município do Rio de Janeiro, RJ (Brasil). Destes, 311 foram classificados como bacterianos e 298 como virais. A maioria destes foi causada pelo vírus ECHO-9, responsável por um surto ocorrido na Zona Sul do Município, a partir de setembro. Foram, apresentadas e discutidas as questões: a) contradição entre significado político e significado epidemiológico dos fatos mórbidos, nem sempre homogêneos; b) ausência de notificação das doenças às autoridades de saúde; c) significado do privilegiamento do espaço geográfico na organização dos serviços de saúde, fato que muitas vezes mascara a verdadeira distribuição da doença e impede um melhor equacionamento das ações no sentido de controlá-las.