7 research outputs found
Effects of vitamin B6 and tryptophan on pork quality and amount of lean meat in gilts of 70–100 kg bodyweight
Supplementary tryptophan in pig diets has shown improvement in carcass traits and pork quality by reducing the animals' response to stress at slaughter. Vitamin B6 could enhance this response since it acts as an enzymatic cofactor of many tryptophan pathways. The present experiment was designed to evaluate dietary vitamin B6 supplementation and tryptophan levels on carcass traits, organ weights, abdominal fat, and pork quality of 70–100 kg gilts. Sixty-four crossbred gilts (initial bodyweight (BW) 70.52 ± 2.95 kg) were distributed in a 2 x 4 factorial scheme, consisting of two supplementary vitamin B6 levels (1 and 5 mg kg-1) and four dietary standardized ileal digestible (SID) tryptophan (Trp) levels (0.140%, 0.167%, 0.194%, and 0.221%). No significant interactions between the dietary SID Trp levels and B6 supplementation were observed on these variables. Vitamin B6 supplementation (5 mg kg-1) showed a minor reduction in meat pH measured 24 hours after slaughter and resulted in a ham yield higher than B6 basal level (1 mg kg-1). The lean meat yield increased linearly as the SID Trp levels increased in the diet. These findings suggested that vitamin B6 supplementation enhanced the pork quality and the increasing levels of SID tryptophan enhanced the lean meat yield of 70–100 kg gilts.Keywords: Carcass yield, meat colour, organ weigh
Partial replacement of DL-Methionine and methionine hydroxy analogue with betaine in diets for broiler chickens
The study evaluated the effects on the growth performance and carcass characteristics of broiler chickens of DL-Methionine (DL-Met) and methionine hydroxy analogue (MHA) supplementation and their partial replacement with betaine (Bet). Two experiments were performed from day 1 to 21 and from day 22 to 42. Broiler chickens were assigned to six treatments, in a completely randomized design and a 2 × 2 + 2 factorial arrangement, consisting of two Met sources (DL-Met and MHA), with or without Bet, and two negative controls. The six treatments consisted of i) NC-DLM: negative control for DL-Met with 7% reduction in DL-Met; ii) NC-MHA: negative control for MHA with 7% reduction of MHA, iii) DLM100: without Bet, supplemented exclusively with DL-Met reaching 100% of requirements, iv) MHA100: without Bet supplemented exclusively with MHA reaching 100% of requirements, v) DLM93+Bet: DL-Met at 93% of recommended level plus betaine; vi) MHA93+Bet: MHA at 93% of recommended level plus betaine. Growth from day 1 to 21 was not altered by methionine source or betaine supplementation. However, the negative controls had numerically less weight gain and feed conversion ratio (FCR) . Between days and 42 there were no effects on growth. Betaine could partially replace methionine without altering the growth of broiler chickens. In addition, the partial replacement of DL-Met with betaine increased body crude protein content. However, its use increased body fat content regardless of methionine source
Nitrogen balance of barrows (15-30 kg) fed low protein and different digestible isoleucine levels
Foram utilizados vinte suÃnos mestiços, ma-
chos castrados, com peso vivo inicial médio de
22,26 ± 1,79 kg; distribuÃdos individualmente em
gaiolas de metabolismo, em um delineamento ex-
perimental de blocos ao acaso, com cinco
tratamentos (0,45; 0,52; 0,59; 0,66; 0,73 % de
isoleucina digestÃvel) e quatro repetições. As
dietas foram formuladas à base de milho e farelo
de soja, com baixa proteÃna bruta (14,15 %), e
diferentes nÃveis de isoleucina digestÃvel. As die-
tas foram umedecidas e fornecidas duas vezes
ao dia (7 e 19 h) para reduzir perdas e facilitar a
ingestão. O perÃodo experimental teve duração de
12 dias, sendo 7 dias para adaptação às gaiolas
metabólicas e rações experimentais e 5 dias de
coleta total de fezes e urina. Posteriormente, foi
determinado o teor de matéria seca das fezes e o
teor de nitrogênio (N) das fezes e urina, bem como
o nitrogênio da uréia plasmática. Foram, então,
calculados o consumo de N, excreção de N (fezes
e urina), N absorvido, N retido, N absorvido/N
retido, N retido/N consumido, N retido/N absorvido
e excreção total de N. Obteve-se significância
(p<0,05) apenas para o nitrogênio ingerido (g/kg
PV 0,75 /dia), em que o modelo linear apresentou
aumento nos valores de N ingerido à medida que
aumentaram os nÃveis de isoleucina digestÃvel nas
rações.Twenty crossbred castrated barrows,
averaging 22.26 ± 1.79 kg of body weight, were
used. The animals were individually alloted in
metabolic cages, in a randomized blocks design,
with five treatments (0.45, 0.52, 0.59, 0.66 and
0.73 % of digestible isoleucine) and four replicates.
The diets were based on corn and soybean meal
with low crude protein (14.15 %) and different
levels of digestible isoleucine. The diets were
humidified and supplied twice a day (7 am and 7
pm) to reduce losses and facilitate ingestion. The
experimental period lasted 12 days, being 7 days
for adaptation to metabolic cages and experimen-
tal diets and 5 days for total feces and urine
collection. Feces were analyzed for dry matter
and nitrogen (N), whereas urine samples were
analyzed for N. The plasma urea nitrogen was also
determined. Then, the N intake, N excretion (feces
and urine), N absorbed, N retention, N retention/N
intake, N retention/N absorbed and total N excretion
were determined. Only N intake (g/kg BW 0.75 /day)
was influenced (p<0.05) by digestible isoleucine
levels, showing a linear increase on N intake as
digestible isoleucine levels increased in the diets
Determinação dos valores energéticos e aminoacÃdicos da silagem de grãos úmidos de milho para frangos de corte
To determine the energy values of high moisture corn silage (SGUM), 120 Cobb Slow male broilers from 21 to 31 days old, with an initial average weight of 765.0 ± 1.7 g, were used, distributed in a completely randomized design, with five treatments (reference ration-RR and replacement levels of SGUM 10, 20, 30 and 40%), in six replicates of four birds each. The experimental period lasted for ten days, five for adaptation and five for collection. The method of analysis was the total excreta collection for the subsequent analysis of its apparent metabolizable energy (EMA) and nitrogen corrected EMA (EMAn) of SGUM. To determine the amino acid values, the technique of forced feeding was applied in 12 cecectomized Leghorn roosters, with an average weight of 1912.10 ± 133.73 g. Six animals received SGUM and the other six were fasted. At the end of the excreta collection period, the essential amino acid profile was determined, as well as, the true digestibility coefficients and the true digestible content of amino acids in the feed. SGUM presented average values of EMA and EMAn of 2283 and 2272 kcal/kg, respectively, and the energy values were negatively affected by the inclusion levels of SGUM. Cystine presented the lowest digestibility coefficient, whereas leucine and glutamine showed the highests digestible amino acids values.Para a determinação dos valores energéticos da silagem de grãos úmidos de milho (SGUM), foram utilizados 120 frangos de corte machos, linhagem Cobb Slow, de 21 a 31 dias de idade, com peso médio inicial de 765,0 ± 1,7 g, distribuÃdos em um delineamento inteiramente casualizado, com cinco tratamentos (ração referência-RR e nÃveis de substituição da SGUM de 10, 20, 30 e 40 %), seis repetições e quatro aves por unidade experimental. O perÃodo experimental teve duração de dez dias, sendo cinco de adaptação e cinco de coleta. O método de análise foi o de coleta total de excretas, para posterior análises de energia metabolizável aparente (EMA) e EMA corrigida pelo balanço de nitrogênio (EMAn) da SGUM. Para a determinação dos valores de aminoácidos, foi usada a técnica de alimentação forçada em 12 galos Leghorn cecectomizados, com peso médio de 1912,10 ± 133,73 g. Seis animais receberam a SGUM e os outros seis permaneceram em jejum. Ao final do perÃodo de coleta de excretas, foi determinado o perfil de aminoácidos essenciais, coeficientes de digestibilidade verdadeira e o conteúdo digestÃvel verdadeiro dos aminoácidos no alimento. A SGUM apresentou valores médios de EMA e EMAn de 2283 de 2272 kcal/kg, respectivamente, sendo que os valores energéticos foram negativamente influenciados pelos nÃveis de inclusão da SGUM. A cistina apresentou o menor coeficiente de digestibilidade, enquanto a leucina e a glutamina apresentaram os maiores valores de aminoácidos digestÃveis
NÃveis de valina digestÃvel para suÃnos machos castrados dos 15 aos 30 kg
The objective of this study was to evaluate the
digestible valine levels for barrows from 15 to 30
kg of weight. In the first experiment, to determine
the nitrogen balance, were used 20 barrows,
averaging 22.88±1.19 kg of initial weight,
individually allotted in metabolic cages in a
randomized blocks design, consisting of five
treatments (0.60, 0.67, 0.74, 0.81, 0.88% of
digestible valine) and 4 replications. In the second
experiment we determined animal performance in
40 barrows, with initial weight of 15.49±0.06 kg,
submitted to the same treatments, experimental
design and replicates used in the first experiment.
The retained N: absorbed N ratio showed a
quadratic effect, indicating 0.748% as an optimum
level of digestible valine. Total N excretion showed
a quadratic effect depending on the digestible
valine levels, being reduced until 0.730% of
digestible valine and from this level the N excretion
increased again. The efficiency of valine utilization
for weight gain decreased linearly as the digestible
valine increased in the diets, and according to the
Linear Response Plateau model was observed a
reduction of this parameter up to 0.790% digestible
valine. It was concluded that the level of 0.748%
of digestible valine was the most appropriate
when considering the retained N: absorbed N
ratio, for barrows from 15 to 30 kg of live weight.O objetivo deste trabalho foi o de avaliar nÃveis
de valina digestÃvel para suÃnos machos castra-
dos, dos 15 aos 30 kg de peso. No primeiro
experimento, para determinação do balanço de
nitrogênio, foram utilizados 20 suÃnos, machos
castrados, com peso inicial de 22,88±1,19 kg,
distribuÃdos individualmente em gaiolas de meta-
bolismo, em delineamento experimental de blocos
ao acaso, constituÃdo de cinco tratamentos (0,60;
0,67; 0,74; 0,81 e 0,88% de valina digestÃvel) e
quatro repetições. No segundo experimento, de
desempenho, foram utilizados 40 suÃnos, machos
castrados, com peso inicial de 15,49±0,06 kg,
submetidos aos mesmos tratamentos, repetições
e delineamento experimental utilizados no primeiro
experimento. A relação N retido:N absorvido
apresentou resposta quadrática, indicando um
nÃvel ótimo de valina digestÃvel de 0,748%. A
excreção total de N apresentou efeito quadrático
em função dos nÃveis de valina digestÃveis, sendo
reduzida até o nÃvel de 0,730% de valina digestÃvel
e a partir deste nÃvel a excreção de N aumentou
novamente. A eficiência de utilização de valina,
para ganho de peso reduziu de forma linear Ã
medida que aumentaram os nÃveis de valina
digestÃvel nas rações, e ao utilizar o modelo linear
response plateou obteve-se a redução deste
parâmetro até 0,790% de valina digestÃvel. Conclui-
se que o nÃvel de 0,748% de valina digestÃvel foi o
mais adequado, ao se considerar o N retido: N
absorvido, para suÃnos machos castrados dos 15
aos 30 kg de peso