Apparent metabolisable energy and amino acid digestibility of microalgae Spirulina platensis as an ingredient in broiler chicken diets.

1. This work investigates the apparent metabolisable energy (AME), its nitrogen-corrected form (AMEn) and amino acid (AA) digestibility coefficients of the microalgae Spirulina platensis as an ingredient in broiler chicken diets. 2. One group of birds was fed with a basal control diet (BD), and another was fed with a test diet composed of the BD with the addition of the microalgae at a proportion of 200 g/kg. AME and AMEn were assessed by total excreta collection and indigestibility analysis using acid-insoluble ash (AIA) as a marker. 3. The microalgae comprised 888.0 g/kg dry matter (DM), 18.42 MJ/kg gross energy, 514.7 g/kg crude protein, 9.9 g/kg ether extract, 10.6 g/kg crude fibre, 94.4 g/kg ash, 3.1 g/kg Ca and 11.0 g/kg P. 4. The values obtained for AME (13.48 MJ/kg DM) and AMEn (11.72 MJ/kg DM) were higher (p < 0.01) than those obtained using the AIA method (9.39-8.29 MJ/kg DM). The microalgae ileal digestibility coefficients were 0.80 ± 0.04 and 0.78 ± 0.04 for essential and non-essential AA, respectively. 5. Overall, the metabolisable energy content and digestibility of AA for S. platensis indicated that the microalgae are potentially an alternative nutrient source for broilers. The AIA method underestimated AME and AMEn in comparison to the total excreta collection method.

Effects of different limestone particle sizes in the diet of broiler breeders post molting on their performance, egg quality, incubation results, and pre-starter performance of their progeny.

An experiment was conducted to test the hypothesis that a coarse limestone diet improves productivity, reproductive performance and the calcium utilization of molted broiler breeders. In total, 640 broiler breeder females, 73-week-old and sixty-four 27-week-old cockerels, Cobb 500, were evaluated during 10 weeks, according to a randomized block design composed of 4 treatments with 8 replicates each. Treatments consisted of diets with the inclusion of 100% fine limestone-fine PS (0.2 mm GMD-geometric mean diameter); PS1: 30% fine limestone+70% limestone with 1.0 mm GMD; PS2: 30% fine limestone+70% limestone with 2.0 mm GMD; and PS3: 30% fine limestone+70% limestone with 3.0 mm GMD. Calcium retention in the gizzard of the breeders, bone characteristics, and breeder performance, egg characteristics, eggshell quality, incubation performance, chick quality and yield, chick pre-starter live performance, and chick bone characteristics were determined. There was no significant difference (P>0.05) in the rate of lay, percentage of non-settable eggs, egg weight, egg shape index, egg specific gravity, eggshell weight, thickness, and percentage hatchability and egg weight loss of broiler breeders fed with diets with different limestone particle sizes. The chick quality and yield, chick pre-starter live performance, and chick bone characteristics were not affected (P>0.05) by any of the limestone particle sizes. It was concluded that live and reproductive performance parameters of broiler breeders post molting is not affected by limestone particle size in the feed.

Vitamin E and selenium in broiler breeder diets: Effect on live performance, hatching process, and chick quality.

This study evaluated the effect of different dietary vitamin E levels and different selenium sources on the productive and reproductive performance of broiler breeders. In total 640 females and 64 males between 22 and 52 weeks old were studied. A completely randomized experimental design in factorial arrangement, with 4 treatments of 8 replicates with 20 females and 2 males each, was applied. Treatments consisted of 2 vitamin E levels (30 and 120 mg/kg) and two selenium sources (sodium selenite and zinc-L-selenomethionine). Egg production (rate of lay and eggs per breeder), egg characteristics (egg, yolk, eggshell, and albumen weights), fertility, incubation responses (egg weight loss during incubation, hatchability, and hatching window), and hatchling characteristics (weight and yield) were evaluated. There was no influence of dietary vitamin E levels or selenium sources on egg production (P > 0.05). Mature breeders (47 weeks old) fed zinc-L-selenomethionine and 120 mg vitamin E/kg feed produced heavier eggs and albumen. Hatchability of the eggs of breeders fed 120 mg vitamin E/kg feed was higher than breeders fed 30 mg vitamin at 29 wks. The dietary inclusion of organic selenium also promoted heavier hatchling weight until egg production peak (33 wk), but did not influence hatchling quality or hatching window. It was concluded that the dietary supplementation of zinc-L-selenomethione and vitamin E (120 mg/kg feed) could be used to improve egg characteristics and incubation response.

Effects of feed form and energy levels on growth performance, carcass yield and nutrient digestibility in broilers.

Feed form is well recognized to improve broiler performance, specially by increasing feed intake (FI). However, when different diet energy levels are used, the results differ in the literature. Therefore, this experiment was conducted to evaluate the influence of feed form and dietary metabolizable energy (ME) levels on broiler performance, carcass yield and on the digestibility of DM, CP, starch and gross energy. In total, 1152 male Cobb 500 broilers were evaluated between 35 and 47 days. The birds were distributed according to a completely randomized design in a 2 × 4 factorial arrangement, consisting of two feed forms (mash or pellet) and four ME levels (12.73, 13.06, 13.40 or 13.73 MJ/kg), totaling eight treatments with eight replicates of 18 birds. Broilers fed the lowest ME level presented the lowest weight gain (WG) and worst feed per unit gain (P < 0.01). Metabolizable energy intake increased (P < 0.01) with progressive increments of ME, which, however, did not affect caloric conversion (CC, P > 0.05). Pelleted diets promoted higher FI, WG, ME intake (P < 0.01) and better feed per unit gain and CC (P < 0.05) compared with mash. In mash diets, increasing dietary ME levels promoted a linear increase in WG (P < 0.01) and reduced feed per unit gain (P ≤ 0.05), but did not affect FI (P > 0.05). In pelleted diets, on the other hand, increasing ME levels linearly reduced FI (P < 0.05) and feed per unit gain (P < 0.01). Broilers fed pelleted diets presented higher abdominal fat deposition than those fed mash (P < 0.05). Increasing ME levels reduced the coefficients of ileal apparent digestibility of DM (P < 0.01) and total starch (P < 0.05) but did not affect the digestibility of other evaluated nutrients. The digestibility of all nutrients was lower when pelleted diets were fed compared with mash. Increasing inert material inclusion in the diets at the expense of soybean oil to reduce dietary ME levels promoted higher pellet durability index values (P < 0.05) and the percentage of fines (P < 0.01). Overall, the results suggest that pelleted diets promote better broiler performance because they increase FI, since the digestibility of dietary fractions is reduced. Chickens consuming low-energy pelleted diets may increase FI to compensate for energy deficit. In contrast, broilers fed mash diets may have reached their maximum intake capacity and did not regulate FI by changing feed energy density. When feeding pelleted diets, dietary energy reduction should be considered to reduce feed costs and to improve the carcass quality of broilers.

Growth of suckling piglets in litters standardized by weight.

This study examined the relationship between birth weight and growth performance when suckling piglets were reared in litters standardized by birth weight. Forty-four gilts (Landrace × Large White) due to farrow during the same week were selected. Piglets born to those gilts were individually weighed at birth and cross-fostered to obtain litters with 11 piglets and standardized birth weight (CV, lower than 5%). Based on average birth weight, 4 litter weight classes were established: class 1 (> 1.10 kg to ≤ 1.33 kg), class 2 (> 1.34 kg to ≤ 1.46 kg), class 3 (> 1.47 kg to ≤ 1.57 kg), and class 4 (> 1.58 kg to ≤ 1.88 kg). At 21 d of age, piglets were weighed to determine BW and calculate ADG and weight gain relative to birth weight. A completely randomized experimental design was used with birth weight classes as treatments. At 21 d of age, the average BW of piglets from the heaviest birth weight class (5.67 kg) was greater (P < 0.05) than the lightest class (5.06 kg); however, all classes had the same ADG (P < 0.05). There was a positive correlation (r = 0.184; P < 0.01) between birth weight and weight at 21 d of age, but birth weight was not correlated (r = -0.040; P = 0.37) with ADG during the suckling phase. Therefore, piglet birth weight did not influence weight gain when piglets were reared by sows in litters with standardized birth weight.

Impact of birth weight and daily weight gain during suckling on the weight gain of weaning piglets / Impacto do peso ao nascimento e ganho de peso na maternidade sobre o ganho de peso dos leitões na creche

This study evaluated the effect of birth weight and weight gain during the suckling phase on the piglet daily weight gain during the nursery phase (21-61 days of age). Piglets (n= 534) derived from 55 first-parity sows were weighed at birth, weaning, and end of the nursery phase. The data were analyzed according to a completely randomized experimental design, with three classes of birth weight (BW) and two classes of weight gain during the suckling phase (SDWG). High BW and low SDWG piglets were 0.2kg lighter at weaning than low BW and high SDWG animals (P< 0.05). However, at the end of the nursery phase, this situation was inverted, with high BW and low SDWG piglets 2.20kg heavier (P< 0.05). Low BW and high SDWG piglets were heavier at weaning and at the end of the nursery phase than low BW and low SDWG piglets (P< 0.05). At the same time, intermediate and high BW and low and high SDWG piglets presented body weight differences at weaning (P< 0.05), but not at the end of the nursery phase (P< 0.05). Piglets with 1.25 to 2.30kg BW and low weight gain during suckling presented a partial compensatory growth during the nursery phase.(AU)

Objetivou-se avaliar o efeito do peso dos leitões ao nascimento e do seu ganho de peso na maternidade sobre seu desempenho na fase de creche (21-61 dias de idade). Quinhentos e trinta e quatro leitões, provenientes de 55 primíparas, foram pesados ao nascimento, no desmame e na saída da creche. Os animais foram distribuídos em um delineamento inteiramente ao acaso, em três classes de peso ao nascimento (PN) e duas classes de ganho de peso diário (GPD) na maternidade. Os animais com alto PN e baixo GPD na maternidade desmamaram 0,2kg mais leves que os animais com baixo PN e alto GPD na maternidade (P<0,05). Porém, os animais com alto PN e baixo GPD na maternidade saíram da creche 2,10kg mais pesados (P<0,05). A diferença aos 21 dias entre os dois tratamentos (alto e baixo GPD) com animais de baixo PN foi de 1,18kg e passou para 2,20kg ao final da creche (P<0,05). No caso dos animais com médio e alto PN, a diferença ao desmame era de 1,14 e 1,26kg e passou para 0,90 e 0,70kg na saída da creche (P<0,05), respectivamente. Leitões com peso ao nascimento entre 1,25 e 2,30kg, com baixo ganho de peso diário na maternidade, apresentaram efeito compensatório parcial no ganho de peso diário durante a creche.(AU)