Modeling amino acid requirements of poultry

Poultry nutritionists should constantly evaluate their feeds and feeding programs in view of the changes that continue to be made to the potential growth rate of broilers and egg production in laying hens with the objective of providing the birds with the optimum economic level of nutrients at all times. In this review, the models generated at Universidade Estadual Paulista (UNESP) Jaboticabal, to estimate the optimum intake of amino acids (AA) for broilers and laying hens are presented. These models were used to estimate the variation in AA intake within a broiler population making use of coefficients of variation that represent the real situation in a commercial broiler operation. The range of AA intakes obtained was compared to some commonly applied feeding programs and recommendations. Based on results of our developed models and other feeding programs, feeds were formulated and growth was predicted using a growth simulation model (Avinesp). The prediction of growth showed that these models are reliable and useful tools to assist the nutritionists in decision making. In a study with laying hens, the Reading model (RM) was used to establish optimum economic AA intakes in a flock of hens. The input variables were the means and standard deviations of egg output and BW, and the relationship between the marginal cost of the AA and the marginal revenue for eggs. Based on this model, the optimum intake of each AA can vary with each of the variables considered. The models proposed in our study enable important decisions to be made regarding AA intakes to be used to obtain optimum economic performance from a population of broilers and laying hens.     

移动棚舍饲养家禽技术初探

移动棚舍饲养家禽，即在田间搭建可移动的棚舍，饲养家禽一定周期后，搬移棚舍，另选场地饲养的一种养殖方式。这种方式饲养家禽具有投资小、疫病少等优点，能有效地改善饲养环境，充分利用自然资源。今年在余姚市采用不同类型的移动棚舍饲养番鸭、三黄鸡都取得了比较好的效果，现就几种不同类的移动棚舍的搭建方法、环境控制要点和饲养效果比较总结如下：１．１简易竹棚移动棚舍简易竹棚移动棚舍的特点是成本低，一般以毛竹、木材为主要材料，棚长１０～１２米，宽５～６米，高２．３～２．５米，造价在３５００元左右，即每平方米６０元左…     

Reliability of indicators of sheep welfare assessed by a group observation method

Assessments of animal-based outcomes form the core of routine veterinary clinical examinations and are being increasingly used as indicators of animal welfare. A method of group observation that did not require gathering and handling of individual sheep, was used to assess eight animal-based indicators of sheep welfare: demeanour, skin irritation, wool loss, excessive panting, coughing, lameness, and cleanliness of the ventral abdominal and 'breech' (perineum/gluteal/caudal hindlimb) areas. The inter-observer reliability of two or three observers who independently assessed these indicators was tested on 2406 adult sheep and growing lambs across 36 farms and the intra-observer reliability of an experienced, veterinary assessor--the 'test standard observer'--was assessed on 88 adult sheep during four on-farm assessments. Observer reliability was evaluated using Cronbach's alpha (α) comparison of the recorded proportion (%) of sheep affected by each welfare condition and by binomial logistic regression modelling. High levels of inter-observer reliability were identified for the assessment of group lameness (α 0.76-1.00) and cleanliness of the breech area (α 0.97-1.00). Excellent intra-observer reliability was determined for lameness (α 0.99), cleanliness of the breech area (α 0.97), demeanour (α 1.00) and wool loss (α 1.00). In addition, proportion data and logistic regression models identified few between-observer differences. The results suggest that welfare outcomes based on observations of the behaviour and physical appearance of individual animals within a group may offer a reliable and feasible measurement tool for the on-farm assessment of sheep welfare.     

Calculation of protein and energy requirements in beluga sturgeon (Huso huso) using a factorial approach

This study tried to determine the protein and energy requirements of growing beluga sturgeon Huso huso using a factorial approach. The experiment was composed of four small‐scale growth trails covering different weight ranges. The fish fed at 0, 20, 40, 60, 80 and 100% of satiation. DWG had a steady increase throughout the experiment following a non‐linear equation as Y = 1.433 (±0.056) × Ln(X) ?2.740 (±0.261); r² = 0.99, p < 0.001, where Y = weight gain (g/day) and X = fish weight (g). The daily requirement of digestible energy (DE) for maintenance amounted to 79.09 kJ × BW (kg)^0.8. The daily requirement of DP for maintenance calculated as 0.93 g × BW (kg)^0.7. The relationship between DE intake (X) and DE gain (Y) expressed as Y = ?0.0004 (±0.000) X² + 0.600 (±0.082) X ?44.95 (± 6.72). Also, the relationship between DP intake (X) and protein gain (Y) was expressed as Y = ?0.019 (±0.006) X² + 0.548 (±0.062) X ? 0.498 (±0.121). The daily requirements of energy and protein were estimated as 79.09 kJ × BW (kg)^0.8 + 2.94 × DE gain and 0.93 g × BW (kg)^0.7 + 2.63 × DP gain. Apparently, beluga sturgeon is inefficient in converting energy and protein into body tissue. Therefore, energy content of the diet should be sufficiently high to satisfy large energy demands in beluga sturgeon and also to reduce the catabolism of protein.     

Blackhead disease (histomoniasis) in poultry: a critical review

After its discovery in 1893 in Rhode Island, blackhead disease was reported across the continent and soon in many other countries. It decimated the turkey industry in New England and followed production like a faithful shadow. Blackhead disease causes high mortality in turkeys, sometimes approaching 100% of a flock. In chickens, the mortality may be 10%-20% with high morbidity, although many outbreaks pass unnoticed. Early workers identified Histomonas meleagridis, a protozoan related to Entamoeba histolytica, Giardia lamblia, and Trichomonas, as the causative agent. Like many other parasites, its life cycle is complex, involving as an intermediate host, the common cecal worm Heterakis gallinarum. The necessity for bacteria for Histomonas to become virulent in the turkey and chicken, notably Escherichia coli, Bacillus subtilis, and Clostridium spp., was discovered by research in gnotobiotic birds. Changes in management brought the disease under control, although it remained the first cause of mortality in turkeys until modern antihistomonal products were developed after WWII. The ban of nitroimidazole products in the United States and Europe was followed by an upsurge in reported cases in turkeys and chickens. Immunization is not an option for prevention, as birds do not reliably become resistant to reinfection after suffering a primary exposure. Recent research demonstrated that histomoniasis could spread rapidly through a flock of turkeys by direct contact, probably involving the phenomenon of cloacal drinking. Direct transmission was not demonstrated for chickens, stressing dependence on H. gallinarum as the source of infection. The lack of suitable treatment drugs or vaccines emphasizes the importance of prevention by worm control and management.     

高效液相色谱法测定鸡饲料中噁喹酸的含量

建立了测定饲料中口恶喹酸含量的高效液相色谱分析方法。采用乙酸乙酯提取饲料中的口恶喹酸。检测条件为:磷酸溶液-乙腈-四氢呋喃(69∶16∶15,V∶V∶V)作为流动相;C18色谱柱;激发波长325 nm;发射波长369 nm。结果表明,浓度在10～500 ng/mL,线性关系良好,r=0.999。在不同浓度添加水平下,三种鸡饲料中口恶喹酸的平均回收率为85.75%～96.77%,日内变异系数为2.24%～9.63%,日间变异系数为2.35%～8.35%,方法检测限为5.0μg/kg,定量限为16.0μg/kg。     

Early history of regulatory requirements for poultry biologics in the United States

Congress passed the Virus-Serum-Toxin Act in 1913, giving the U.S. Department of Agriculture (USDA) authority to prevent the importation or interstate shipment of worthless, contaminated, dangerous, or harmful veterinary biological products. The passage of this act marked the beginning of regulatory requirements for veterinary biological products in the United States. In 1913, only a few biologics establishments produced products for the poultry industry. The first license issued by the USDA for a poultry product was in 1918 to the University of California, Berkeley, for fowlpox vaccine. The list of biological products for poultry grew slowly in the 1920s. However, this began to change with the licensing of laryngotracheitis vaccine in 1933; pigeonpox vaccine in 1939; several Newcastle disease vaccines (inactivated in 1946, Roakin strain in 1948, B1 strain in 1950, and La Sota strain in 1952); and the first bronchitis vaccine in 1953. With the development of these and other new products, the biologics industry began to move its emphasis on hog cholera serum and virus to one based on the production of numerous new vaccines and bacterial products. The USDA's approach to the regulation of biologics in the early 1950s was still geared to the production of hog cholera products; however, as a result of the intervention of a group of dedicated poultry scientists, who were concerned about the poor performance of Newcastle disease vaccines, this soon changed. This presentation describes the initiation and development of modern standards for poultry biologics that occurred as a result of this intervention. The development and improvement of standards and regulatory requirements to address mycoplasma, leukosis, and other extraneous virus contaminations in chicken embryo origin products are reviewed. The licensing of products to meet new and emerging disease problems in the poultry industry and the close interaction among research scientists, poultry industry, biologics manufacturers, and government regulatory officials that has been needed to ensure the availability of products that meet appropriate standards of purity, safety, potency, and efficacy are also addressed.     

A simple and efficient method for isolation of a single Eimeria oocyst from poultry litter using a micromanipulator

The chicken, which is the host for seven species of Eimeria, typically is infected simultaneously by multiple Eimeria species and the oocysts of coccidia are excreted in the feces. A prerequisite for investigation of individual Eimeria species is to isolate a single oocyst from fecal samples. A novel method for isolating a single Eimeria oocyst from poultry litter using a micromanipulator was developed. This simple method is fast and reliable, and provides direct isolation of a single sporulated oocyst from fecal samples harboring multiple Eimeria species or samples contaminated by other species of parasite.     

Nutrient requirements of poultry publication: History and need for an update

The NRCNutrient Requirements of Poultry has been a benchmark publication for the research, judicial, and regulatory communities domestically and abroad since the first published edition in 1944. The poultry scientific community has looked to this publication for benchmark diet formulation. With extraordinary changes in growth and productive potential of modern poultry strains, as well as changes to body composition and egg output, it follows that nutrient needs have changed beyond what the bird can compensate for with increasing intake per unit of BW. Research publications used for amino acid and phosphorus recommendations in the last NRC are now, at best, from 1991 and at worst from 1947. To our collective credit, the poultry science community has published substantial amounts of data in those areas to warrant an update to the ninth revised edition of the NRCNutrient Requirements of Poultry. Historically, our perception and definition of a nutrient requirement has changed from first being a requirement, as a percent of a diet, to preventing a nutrient deficiency, to now being a requirement to optimize growth or egg production response per unit of nutrient intake. As economics becomes an increasingly more important driver for the implications of research, the scientific community has begun to embrace the concept of return on investment of nutrient used for compositional growth or egg production. As these concepts take shape, the current edition's format will have to undergo a substantial creative revision; possibly even embracing the concept of modeling of nutrient responses. Funding for such a revision will require a large financial investment from the NRC, the feed industry, commodity associations, as well as time investment by the scientific community.     

Establishing an essential amino acid profile for maintenance in poultry using deletion method

This study aimed to estimate the essential amino acid profile and the ideal ratio for the maintenance of poultry by deletion method. A nitrogen balance (NB) trial was conducted using 198 adult roosters, housed individually in metabolic cages. The treatments were 33 purified diets being 11 diets with an amino acid mixture providing high protein intake of 500 mg N/BW_kg^0.75 per day, 11 diets providing medium protein intake of 250 mg N/BW_kg^0.75 per day (in each diet, one amino acid tested was diluted 50%) and 11 diets providing low protein intake of 125 mg N/BW_kg^0.75 per day (made by omitting the amino acid tested). Each treatment had six replicates. After 48 h of fasting receiving water plus sucrose, the roosters were fed 40 g of the diets by tube once a day for 3 days. The excreta were collected within 72 h after the first feeding. The diets and excreta were analysed for nitrogen content. For each amino acid studied, a linear regression was fitted by NB and amino acid intake (AAI). The maintenance requirements were estimated as the AAI to maintain the NB equal to zero. The daily amino acid requirements for maintenance were estimated to be Lys 11, Met 29, Thr 23, Trp 5, Arg 50, Val 29, His 6, Gly 54, Phe 49, Leu 78 and Ile 21 mg/BW_kg^0.75 per day. Therefore, the amino acid ratio for maintenance was concluded to be Lys 100, Met 276, Thr 220, Trp 48, Arg 467, Val 275, His 60, Gly 511, Phe 467, Leu 735 and Ile 198% independent of the scale. The essential amino acid profile and the ideal ratio for the maintenance of poultry estimated in this study contributed to improve the factorial model for estimating essential amino acid requirements for poultry.     

家禽加工副产品的利用

综合目前所有研究得出的一致结论是:经过正确加工处理后的家禽副产品,都是优质的饲料原料。如果想提高家禽副产品的利用价值,就必须了解其适宜的加工条件及每种动物在各个生长阶段的饲喂量。下面是从美国家禽和禽蛋协会资助的www.poultryegg.org网站摘编的关于家禽蛋白质副产品     

Head-only electrical stunning of poultry using a waterbath: a feasibility study

1. The objective of this work was to investigate the feasibility of head only waterbath stunning as a means of generating immediate and long lasting unconsciousness while preventing wing flapping and avoiding carcass damage. 2. EEG measurements showed that immersion of the heads of the broilers for one second in a waterbath containing water of conductivity 2 x 5 mS/cm and a 50 Hz electric field of 10 V/cm resulted in immediate unconsciousness, and that increasing the electric field strength extended the duration of unconsciousness. 3. The passage of a 25-30 mA alternating current of frequency 2000 Hz through the broilers' bodies suppressed the wing flapping that followed a stun. 4. When the body current and electric field were applied simultaneously, wing flapping was prevented and EEG signals were suppressed for over 30 seconds indicating that the immediate unconsciousness lasted long enough to facilitate humane slaughter.     

Spatial requirements of animals: Allometry and beyond

Space allowance is a major factor influencing animal welfare. For livestock, at least, it plays a critical role in profitability, yet there is little information on the amount of space that animals require. The amount of space an animal occupies as a consequence of its shape and size can be estimated using allometry; linear dimensions (L) can be expressed as L = kW^1/3 and surface area (S) as S = kW^2/3, where k = a constant and W = the weight of the animal. Such equations have been used to determine the amount of space needed by standing (area [m²] = 0.019W^0.66) and lying (area [m²] = 0.027W^0.67) animals. Limited studies on the lying down and standing up behaviors of pigs and cattle suggest that the amount of space required can be estimated by area (m²) = 0.047W^0.66. Linear space required per animal for behaviors such as feeding or drinking from a trough can be estimated from 0.064W^0.33, but in groups this requirement will be affected by social interactions among group members and the amount of competition for the resource. Determining the amount of space for groups of animals is complex, as the amount of useable space can vary with group size and by how group members share space in time. Some studies have been conducted on the way in which groups of domestic fowl use space, but overall, we know very little about the ways in which livestock time-share space, synchronicity in the performance of behaviors, and the effects of spatial restrictions on behavior and welfare.     

Dermatitis in a horse associated with the poultry mite (Dermanyssus gallinae)

This is the first documented case report of dermatitis associated with the poultry mite (Dermanyssus gallinae) in a horse. It occurred in a 16-year-old horse that was in contact with domestic hens. Clinical signs consisted of severe pruritus, with self-induced hair loss mainly on the head. Despite the multiple skin scrapings performed during both day- and nighttime, mites were only isolated from the in-contact poultry and from the horse's environment, and not the horse. The animal was treated using a 2% permethrin solution, sprayed on the entire body once a week for 4 weeks, and by decontamination of the horse's immediate environment. Although eradication of the mites and elimination of further contact between the horse and the poultry were not achievable, recurrence of dermatitis was prevented by regular applications of permethrin on the horse and biannual decontamination of the horse's stable.