Estratégias nutricionais com redução da proteína bruta e aumento de aminoácidos livres para suínos em terminação sob condição de estresse cíclico por calor
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Data
2022-07-29
Autores
Azevedo, Paulo Henrique Amadeu de
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo desse estudo foi avaliar os efeitos de dietas com baixa proteína
suplementadas com AA industriais sobre o desempenho e a composição corporal de suínos sob
ECC. Para isso, foram utilizadas 90 fêmeas suínas (Landrace × Large White) [Agroceres PIC Camborough] (67,7 ± 6,2 kg), durante um período experimental de 48 dias, dividido em 2 fases
alimentares. A primeira fase alimentar com duração de 27 dias (D0 a D27) correspondeu à fase
de terminação I (67 a 93 kg). A segunda fase alimentar com duração de 21 dias (D27 a D48)
correspondeu à fase de terminação II (93 a 112 kg). Os animais foram distribuídos em um
delineamento experimental de blocos casualizados, em um esquema fatorial 2 × 3: duas
temperaturas ambiente (TA) e três estratégias nutricionais (EN), com 15 repetições, sendo cada
animal considerado uma unidade experimental. Os blocos foram formados de acordo com o
peso inicial dos animais, dividindo-os em blocos de animais leves, médios e pesados. As TA
foram: termoneutralidade (TN), no qual os animais foram mantidos a temperatura constante de
22 ºC por 24 h; e estresse cíclico diário por calor (ECC), que compreendeu aos suínos um
desafio diurno de 35 ºC das 8 às 20 h, seguido de um período noturno de TN (22ºC das 20 às 8
h). As EN foram: AP, alta PB, dieta formulada sem a inclusão de AA industriais; BPAA, baixa
PB, dieta suplementada com AA industriais; BPAA+, dieta com suplementação extra de AA
industriais, sendo a suplementação extra de +20% de lisina digestível acima da recomendação
para a fase, com ajustes nas relações Lis:AA (Met+Cis: 65%, Tre: 72%, Tri: 20%, Val: 70%,
Ile: 54%). As dietas atenderam ou excederam as exigências nutricionais aminoacídicas
recomendadas pelo NRC. No início do experimento a composição corporal dos animais foi
determinada pelo DXA. Ao final de cada fase alimentar foi avaliado o desempenho dos animais
e a composição corporal (proteína e gordura). Não foram observadas interações TA x EN
(p>0,10), assim como efeito das EN (p>0,10) sobre o desempenho dos animais. Na fase de
alimentação 1, os animais do ambiente ECC reduziram o consumo de ração (p=0,02), tendo
uma melhor eficiência alimentar (p=0,04). Durante a fase de alimentação 2, o consumo de ração
(p<0,01), o ganho de peso (p<0,01), bem como o peso final (p=0,03) foram afetados
negativamente, sem alterar a eficiência alimentar (p>0,10). Em geral, suínos sob ECC
reduziram o consumo de ração (p<0,01), o ganho de peso (p=0,03) e o peso final (p=0,03). Não
foram observadas interações TA x EN (p>0,10) sobre as variáveis de composição corporal, nem
efeito das EN (p>0,10). Animais criados em ECC reduziram o lipídeo corporal (p=0,03) e o
conteúdo mineral ósseo (p=0,03). O modelo experimental de EC mimetizado neste estudo
evidencia os efeitos deletérios da alta temperatura sobre o desempenho e composição corporal
dos suínos. As EN não foram eficientes em atenuar os efeitos do EC sobre o desempenho e
composição corporal. A redução do nível de proteína da dieta não afetou o desempenho dos
suínos. A suplementação de AA acima das recomendações aumentou a deposição de lipídeos
de suínos durante a segunda fase de terminação.
The aim of this study was to evaluate the effects of low protein diets supplemented with industrial AA on performance and body composition of swine under ECC. For this, 90 sows (Landrace × Large White) [Agroceres PIC Camborough] (67.7 ± 6.2 kg) were used during an experimental period of 48 days, divided into 2 feeding phases. The first feeding phase lasting 27 days (D0 to D27) corresponded to the finishing phase I (67 to 93 kg). The second feeding phase lasting 21 days (D27 to D48) corresponded to the finishing phase II (93 to 112 kg). The animals were distributed in a randomized block experimental design, in a 2 × 3 factorial scheme: two ambient temperatures (AT) and three nutritional strategies (EN), with 15 replications, with each animal considered an experimental unit. The blocks were formed according to the initial weight of the animals, dividing them into blocks of light, medium and heavy animals. The AT were: thermoneutrality (TN), in which the animals were kept at a constant temperature of 22 ºC for 24 h; and daily cyclical heat stress (ECC), which included a daytime challenge of 33,8 ºC from 8 am to 8 pm, followed by a nocturnal NT period (22ºC from 8 pm to 8 am). The EN were: AP, high CP, diet formulated without the inclusion of industrial AA; BPAA, low CP, diet supplemented with industrial AA; BPAA+, diet with extra industrial AA supplementation, with an extra supplementation of +20% digestible lysine above the recommendation for the phase, with adjustments in Lis:AA ratios (Met+Cys: 65%, Thr: 72%, Tri: 20%, Val: 70%, Ile: 54%). The diets met or exceeded the amino acid nutritional requirements recommended by the NRC. At the beginning of the experiment the body composition of the animals was determined by DXA. At the end of each feeding phase, the animals' performance and body composition (protein and fat) were evaluated. There were no TA x EN interactions (p>0.10), as well as the effect of EN (p>0.10) on the animals' performance. In the feeding phase 1, the animals of the ECC environment reduced the feed consumption (p=0.02), having a better feed efficiency (p=0.04). During feeding phase 2, feed intake (p<0.01), weight gain (p<0.01), as well as final weight (p=0.03) were negatively affected, without changing the feed efficiency (p>0.10). In general, pigs under ECC reduced feed intake (p<0.01), weight gain (p=0.03) and final weight (p=0.03). There were no TA x EN interactions (p>0.10) on body composition variables, nor effect of EN (p>0.10). Animals raised in ECC reduced body lipid (p=0.03) and bone mineral content (p=0.03). The experimental model of EC mimicked in this study evidences the deleterious effects of high temperature on the performance and body composition of pigs. The EN were not efficient in attenuating the effects of EC on performance and body composition. Reducing the level of protein in the diet did not affect the performance of the pigs. AA supplementation above the recommendations increased the lipid deposition of pigs during the second finishing phase.
The aim of this study was to evaluate the effects of low protein diets supplemented with industrial AA on performance and body composition of swine under ECC. For this, 90 sows (Landrace × Large White) [Agroceres PIC Camborough] (67.7 ± 6.2 kg) were used during an experimental period of 48 days, divided into 2 feeding phases. The first feeding phase lasting 27 days (D0 to D27) corresponded to the finishing phase I (67 to 93 kg). The second feeding phase lasting 21 days (D27 to D48) corresponded to the finishing phase II (93 to 112 kg). The animals were distributed in a randomized block experimental design, in a 2 × 3 factorial scheme: two ambient temperatures (AT) and three nutritional strategies (EN), with 15 replications, with each animal considered an experimental unit. The blocks were formed according to the initial weight of the animals, dividing them into blocks of light, medium and heavy animals. The AT were: thermoneutrality (TN), in which the animals were kept at a constant temperature of 22 ºC for 24 h; and daily cyclical heat stress (ECC), which included a daytime challenge of 33,8 ºC from 8 am to 8 pm, followed by a nocturnal NT period (22ºC from 8 pm to 8 am). The EN were: AP, high CP, diet formulated without the inclusion of industrial AA; BPAA, low CP, diet supplemented with industrial AA; BPAA+, diet with extra industrial AA supplementation, with an extra supplementation of +20% digestible lysine above the recommendation for the phase, with adjustments in Lis:AA ratios (Met+Cys: 65%, Thr: 72%, Tri: 20%, Val: 70%, Ile: 54%). The diets met or exceeded the amino acid nutritional requirements recommended by the NRC. At the beginning of the experiment the body composition of the animals was determined by DXA. At the end of each feeding phase, the animals' performance and body composition (protein and fat) were evaluated. There were no TA x EN interactions (p>0.10), as well as the effect of EN (p>0.10) on the animals' performance. In the feeding phase 1, the animals of the ECC environment reduced the feed consumption (p=0.02), having a better feed efficiency (p=0.04). During feeding phase 2, feed intake (p<0.01), weight gain (p<0.01), as well as final weight (p=0.03) were negatively affected, without changing the feed efficiency (p>0.10). In general, pigs under ECC reduced feed intake (p<0.01), weight gain (p=0.03) and final weight (p=0.03). There were no TA x EN interactions (p>0.10) on body composition variables, nor effect of EN (p>0.10). Animals raised in ECC reduced body lipid (p=0.03) and bone mineral content (p=0.03). The experimental model of EC mimicked in this study evidences the deleterious effects of high temperature on the performance and body composition of pigs. The EN were not efficient in attenuating the effects of EC on performance and body composition. Reducing the level of protein in the diet did not affect the performance of the pigs. AA supplementation above the recommendations increased the lipid deposition of pigs during the second finishing phase.
Descrição
Palavras-chave
Aminoácidos na nutrição animal, Suinocultura, Rações