S. L. Vieira

Effects of a monocomponent protease on performance and protein utilization in 7- to 22-day-old broiler chickens

A study was conducted with an exogenous monocomponent protease added to corn-soybean meal diets fed to straight-run Ross 708 broilers from 7 to 22 d of age. Broilers were randomly placed into 42 battery pens (5 birds/pen) and allocated to 6 treatments with 7 replicates. A positive control diet (PC; 22.5% CP) and a low protein basal diet (20.5% CP) were formulated. Low protein diets (LP) comprised 98.67% of low protein basal diet and 1.33% Celite (indigestible marker and filler; Celite Corp., Lompoc, CA). Protease [75,000 PROT units/g; 1 PROT unit is defined as the amount of enzyme that releases 1 µmol of p-nitroaniline from 1 µM of substrate (Suc-Ala-Ala-Pro-Phe-p-nitroaniline per minute at pH 9.0 and 37°C] was added at the expense of Celite (0 mg/kg, LP0; 100 mg/kg, LP100; 200 mg/kg, LP200; 400 mg/kg, LP400; and 800 mg/kg, LP800) to create the LP diets (20.25% CP). At 22 d of age, ileal contents were collected from all birds for apparent CP and amino acid (AA) digestibility determinations. Broilers fed the PC diet were 7.5% heavier (P < 0.05) compared with those fed the LP0 diet. Birds fed the LP diets containing protease regardless of concentration grew as well as the birds fed the PC diet. Feed conversion was impaired (P < 0.05) in birds fed the LP0 and the LP100 diets compared with those fed the PC diet, but no difference was found between birds fed the PC diet and those fed diets containing more protease (LP200, LP400, and LP800). Digestibility of CP was increased (P < 0.05) in broilers fed the LP-supplemented diets compared with those fed either the PC or LP0 diets, but it was similar between those fed LP diets with any protease concentration. Digestibility of AA was not different between the PC and LP0 diets. The protease used in this study restored live performance and digestibility of CP (6.1%). When benefits in AA digestibility occurred, they were similar at all protease inclusions and averaged as follows: Arg, 3.5%; Ile, 3.2%; Lys, 5.4%; Thr, 7.8%; Asp, 6.5%; His, 3.3%; Cys, 4.6%; and Ser, 5.5%. Methionine was increased only at 400 and 800 mg/kg (6.5%) and Val was increased only at 200 and 800 mg/kg (5%).

Utilização da Energia de Dietas para Frangos de Corte Formuladas com Óleo Ácido de Soja

Acidulated soapstock, a by-product from the vegetable oil industry has been widely used in poultry nutrition. It is produced by the acid treatment of the residue left after refining vegetable oils. Several concerns exist on the use of this product, such as: adulteration, peroxidation, impurity, and uncertain energetic value. The current experiment focused on the use of the acidulated soapstock in broiler feeds compared with soybean oil. Feeds formulated with 4 and 8% added acidulated soapstock or soybean oil or their mixture in the ratios of 2 : 2 and 4 : 4 % were given to 7 day-old broiler chicks to 42 days of age placed in heated batteries. Birds receiving the diets with acidulated soapstock plus soybean oil had lower body weight at the end of the experiment when compared with birds on the treatments exclusively prepared with acidulated soapstock or soybean oil. This response was independent of the level of oil inclusion. Birds on the lower inclusion level consumed more feed, regardless of the oil source and showed poorer feed conversions, but did not show reduction in body weight when compared to the higher level of inclusion. Acidulated soapstock demonstrated an excellent potential as an energy supplement to be used in broiler feeds and had its energetic value determined as 8.114 kcal EMAn/kg DM, 5% below the value determined for soybean oil.

Chicken embryo utilization of egg micronutrients

IntroductionAvian embryos develop and grow from energy and nutrients storedin the egg by the hen. In this sense, breeder male contribution is notimportant. Follicular deposition of nutrients occurs over a wide range oftime, but becomes relevant during the week prior to ovulation. Amounts,but also forms, of nutrients deposited in the egg determine success ofembryo development and hatching of a healthy chick. To support theembryo during incubation, oxygen is the only nutrient not derived fromthe egg; however, adequate oxygen concentrations in the surroundingair and its free passage through well-established shell membraneporosities are essential. Developmental limitations and embryo mortalityare aggravated when any inadequacy in these conditions prevail.Macroscopically, the fertile egg has three components: shell, yolk,and albumen. Specific nutrients are mobilized by the embryo from eachof these parts. These typically have expected compositions, which arenotably affected by the hen’s nutrition.After oviposition, the egg may be submitted to changes due to inovo injection using the vaccination equipment routinely used inhatcheries. However, these injections are limited to small amounts, andpreferably done with more available forms of micronutrients. Researchon this matter is recent and usually directed to metabolic interventions,such as the role of substances which stimulate or mediate enzymetranscription.Egg ReservesMacroscopically, the egg is a simple structure with three majorcomponents (shell, albumen, and yolk), demonstrating uniquecharacteristics and playing specific roles during incubation. It is generallyagreed that each egg is built with a complete capacity to produce aperfect new organism. However, due to several reasons, this is notalways the case. In general, the composition of macromolecules in eggsis more constant than those elements usually found in a lower proportion,such as micronutrients. Since all egg constituents derive from the hen’sorganism, metabolic transformation of the hen’s feed is needed toobtain adequate embryo development and viable chicks at hatching.Egg shells consist of two main components: a matrix of protein fibersand col umns of calcium carbonate crystals in a proportion of 1:50 (Romanoff& Romanoff, 1949). A glycoprotein layer, the cuticle, covers the crystalsurface, and it is the last egg component to be deposited before oviposition.The cuticle has three main functions: prevention of excessive water loss(Peebles & Brake, 1986), protection from microbial infection (Roussel et al.,1988), and termination of calcite crystal growth (Dennis et al., 1996). Theshell matrix presents two regions: a mammillary region, connected to theouter shell membrane protein fibers, and a spongy one, associated to calcitecrystals deposited in layers on the mammillary matrix (Simkiss, 1968).

Chelated minerals for poultry

Organic minerals have been subject of an increasing number of investigations recently. These compounds can be considered the most significant event regarding commercial forms of minerals targeting animal supplementation in the last decades. Minerals, especially metals, are usually supplemented in poultry feeds using cheap saline sources and have never required a lot of attention in terms of quality. On the other hand, definitions of organic minerals are very broad and frequently lead to confusion when decision-making becomes necessary. Organic minerals include any mineral bound to organic compounds, regardless of the type of existing bond between mineral and organic molecules. Proteins and carbohydrates are the most frequent candidates in organic mineral combinations. Organic fraction size and bond type are not limitations in organic mineral definition; however, essential metals (Cu, Fe, Zn, and Mn) can form coordinated bonds, which are stable in intestinal lumen. Metals bound to organic ligands by coordinated bonds can dissociate within animal metabolism whereas real covalent bonds cannot. Chelated minerals are molecules that have a metal bound to an organic ligand through coordinated bonds; but many organic minerals are not chelates or are not even bound through coordinated bonds. Utilization of organic minerals is largely dependent on the ligand; therefore, amino acids and other small molecules with facilitated access to the enterocyte are supposed to be better utilized by animals. Organic minerals with ligands presenting long chains may require digestion prior to absorption. After absorption, organic minerals may present physiological effects, which improve specific metabolic responses, such as the immune response. Many studies have demonstrated the benefits of metal-amino acid chelates on animal metabolism, but the detection positive effects on live performance is less consistent.

Hatching distribution of eggs varying in weight and breeder age

Broiler chicks from one incubator hatch within long periods of time, which leads to dehydration and reduction in yolk sac reserves of those chicks that have hatched earlier and potentially impairs early performance. The present research investigated the hatching distribution at intervals of incubation using eggs of different weights within one breeder age or eggs from widely different breeder ages. Eggs from breeders at 27 and 59 weeks of age (54 and 69 g) and from breeders at 40 weeks of age, which were graded as light (58 g) and heavy (73 g), were placed in a commercial incubator. There were a total of 1,184 eggs distributed in four treatments and eight replicates: eggs from 27-week-old breeders (27B), eggs from 59-week-old breeders (59B), light eggs from 40-week-old breeders (40BL) and heavy eggs from 40-week-old breeders (40BH). Replicates were comprised of 37 eggs that were placed in each incubator tray. The treatments were physically separated from each other using a plate. Eggs were transferred to a hatcher after 432 hours of incubation and the first chick hatched at 449 hours of incubation. Afterwards, the number of completely hatched chicks from each replicate was recorded at six-hour intervals until 503 hours of incubation, when the hatchings stopped. Hatched chicks were removed from the trays after each measurement. Data were submitted to an analysis of variance with repeated measures. There was a significant interaction between breeder age and incubation length. The hatching onset of eggs from the old breeders was later compared to young breeders. Hatchability (%incubated eggs) was lower for the old breeders; however, differences in hatchability as a percentage of the hatched eggs were not so evident. Complete hatchability occurred only at 503 hours of incubation; however, more than 90% eggs had hatched 18 hours earlier.

Suplementação de acidificantes orgânicos e inorgânicos em dietas para frangos de corte: desempenho zootécnico e morfologia intestinal

The effect of supplementation of acidifiers in diets for broiler chicks on performance na intestinal morphology was valuated. A total of 2,112 birds was allocated to eight diets, with six replicates, constituted by the addition of antibiotics or acidifiers blenders according to the phase development (from 1 to 7, from 8 to 21 and from 22 to 35 days old), in different composition: control - positive = bacitracin methylene disalicylate (BMD - 55 ppm) + colistin (10 ppm); control-negative = without antibiotic growth promoters or acidifiers; blend A = 8, 4.5 and 2.5 kg/t; blend B = 10, 6 and 3 kg/t; blend C = 4, 2 and 1 kg/t; blend C = 3, 3 and 1 kg/t; blend D = 5, 2.5 and 1 kg/t and blend D = 3, 3 and 1 kg/t. There was a general benefit with the use of acidifiers on feed conversion, which was similar to the use of antibiotics, except for blend B. Small intestine of birds of control-negative was heavier and had shorter villi height. The deeper Lieberkuhn crypt depth was not altered by the antibiots and by great part of the acidifiers. The use of acidifiers was efficient in maintenance of performance and morphological conditions of small intestines of broilers chicks, similar to the benefit of the use of antibiotics, except for Blend B. There was no difference among the blenders thea could be attributed the different composition, except for the duodenal crypt depth for birds fed Blend D (3/3/1 kg/t).

Development of bone in chick embryos from Cobb 500 breeder hens fed diets supplemented with zinc, manganese, and copper from inorganic and amino acid-complexed sources

Sources of Zn, Mn, and Cu (IZMC) as sulfates or as amino acid complexes (OZMC) were used to supplement Cobb 500 breeder hen diets. Experimental treatments consisted of diets supplemented with 1) 100, 100, and 10 mg/kg of Zn, Mn, and Cu, respectively, from IZMC (control); 2) 60, 60, and 3 mg/kg of Zn, Mn, and Cu, respectively, from IZMC plus 40, 40, and 7 mg/kg of Zn, Mn, and Cu, respectively, from OZMC (ISO); and 3) a diet with 100, 100, and 10 mg/kg of Zn, Mn, and Cu, respectively, from IZMC as in control plus 40, 40, and 7 mg/kg of supplemental Zn, Mn, and Cu from OZMC (on top). Ten replications of 20 females and 2 males were used per treatment. Eggs from breeders at 30, 40, 50 and 60 wk of age were incubated, and 5 embryos per replicate were collected at 10 (E10), 14 (E14), and 18 (E18) d of incubation. Midshaft width and calcification were measured for left tibia and femur stained with Alcian Blue and Alizarin Red S. At hatch, the left tibia of 5 chicks per replicate was sampled for histological evaluation of the diaphysis and distal epiphysis. Feeding the ISO treatment compared with the control diet increased the Zn (P < 0.05) but not Mn and Cu content of the yolk and albumen blend. At E14, the ISO and on-top treatments had a trend to increase tibia calcification at the rates of 1.6 and 1%, respectively (P < 0.1). The E18 ISO and on-top treatments had 2% thicker tibia compared with the control, regardless of hen age (P < 0.05). Also, at E18, calcification of tibia and femur was higher from hens fed the on-top treatment (P < 0.05). The chicks from the ISO and on-top groups had increased tibia moment of inertia (P < 0.01) at day of hatch. Broiler breeder hens consuming OZMC associated with IZMC produced embryos and hatching chicks with improvements in selected bone mineralization parameters.

Ascorbic acid and citric flavonoids for broilers under heat stress: effects on performance and meat quality

The aim of this study was to evaluate the effects of increasing doses of ascorbic acid (AA) and citric flavonoids (quercetin and rutin) on the performance and meat quality characteristics of broilers submitted to cyclic heat stress. Four-hundred one-day-old female Ross 308 were housed in 40 battery cages a in temperature controlled room. Treatments consisted of 0, 250, 500, and 1000 g/ton on of AA + citric flavonoids. Birds were fed ad libitum until 32 day of age. Beginning on day 14 posthatch until the end of the experiment, in order to simulate cyclic heat stress, the temperature inside the room was increased to 32°C for 5 hours, and decreased until reaching the comfort temperature corresponding to the age of the animals. Birds were slaughtered at 33 days of age, and carcass and commercial cuts yields were determined. Thighs and boneless breast samples were collected and frozen for subsequent analyses of pH, cooking loss, shear force, color, and Thiobarbituric Acid Reactive Substances (TBARS). Significant differences (p <0.05) were found for feed efficiency from 1 to 7 days of age, with the best values for the birds fed 0 and 250 g/ton on of AA + citric flavonoids. At the end of the experiment, there were no differences in other performance variables, carcass and parts yields, pH, shear force, color and TBARS. The meat of the birds supplemented with 250 g/ton on of product presented the lowest cooking loss.

Hatching distribution and embryo mortality of eggs laid by broiler breeders of different ages

This study investigated the hatching distribution of eggs from broiler breeders of different ages in distinct periods of incubation. Eggs were incubated in a single-stage experimental incubator. A number of 3.510 eggs were distributed into 3 treatments with 13 replicates of 90 eggs each. Treatments corresponded to breeder age: young (34 weeks), intermediate-age (44 weeks) and old (72 weeks) breeders. Eggs were transferred to the hatcher at 432 incubation hours, hatching was first checked at 449 hours, after which the number of hatched chicks was counted every 6 hours up to 515 incubation hours. After each count, hatched chicks were removed from the hatcher. Data were submitted to analysis of variance using measures repeated. A significant interaction between breeder age and incubation time was found. The total period required to hatch all incubated fertile eggs was not influenced by breeder age, which, however, affected hatching distribution. Eggs from old breeders hatched later as compared to young and intermediate-age breeders. More than 71% of the eggs had already hatched at 485 incubation hours, and 94% at 491 hours. Eggs laid by old breeders presented higher infertility and total embryo mortality, resulting in lower hatching percentage.

Starch digestibility, energy utilization, and growth performance of broilers fed corn-soybean basal diets supplemented with enzymes

A study was conducted to evaluate the effects of dietary α-amylase and β-xylanase supplementation of corn-soy diets, formulated with or without supplemental phytase, on growth performance, energy utilization, and starch digestibility in broiler chickens. A total of 336 slow-feathering, Cobb × Cobb 500 male broilers were randomly distributed to 6 treatments having 8 replicates of 7 birds each. Birds were fed a common starter diet to d 14 post-hatch (3,050 kcal/kg AMEn, 21.7% CP, 1.05% Ca, and 0.53% nPP). The experimental diets were provided afterwards until d 25. A 2 × 3 factorial arrangement of 2 control diets (basal = corn-soy diet without added phytase or PHY = corn-soy diet formulated with 1,000 phytase units/kg) and 3 carbohydrase supplementations (0, 80 kilo-Novo α-amylase units/kg, or 80 kilo-Novo α-amylase units/kg + 100 fungal β-xylanase units/kg) was used from d 14 to 25. Excreta were collected from 21 to 24 d and all birds were euthanized at 25 d for jejunum and ileum content collection. Samples of feed, excreta, and jejunal and ileal digesta were analyzed for determination of total tract retention and ileal apparent digestibility. No interactions between diet and carbohydrase were observed. Broilers fed diets formulated with phytase or supplemented with amylase + xylanase had higher BW gain (BWG) and lower FCR (P < 0.05) when compared with birds fed diets without carbohydrases. Relative to the basal diet, AMEn was increased (P < 0.01) by 70 kcal/kg and 99 kcal/kg when birds were fed the diet supplemented with amylase and amylase + xylanase, respectively. Starch digestibility in the jejunum and ileum was increased (P < 0.05) by 3.5% and 2.4%, respectively, when birds were fed the diet supplemented with amylase + xylanase. Results from this experiment show that corn-soy diets having phytase and supplemented with amylase and xylanase led to increased growth performance, AMEn, and starch digestibility in broilers. Furthermore, the efficacy of exogenous amylase and xylanase was independent of the presence of microbial phytase.