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The study aimed at evaluating the effects of high ambient temperature (HT: 30 °C) on the thermoregulatory responses and performance of commercial and Piau crossbred (Brazilian Piau breed sires × commercial genotype dams) growing pigs. Commercial and Piau crossbred pigs were reared under thermoneutral (TN: 22 °C) or HT conditions during a 14-day experimental period. Feeding (daily) and animals (beginning and end) were weighted to obtain performance parameters. Skin and rectal temperatures, respiratory rate, and blood parameters were also measured. At the end of the trial (day 15), the animal’s backfat thickness (BF) and loin eye area (LEA) were measured. No interaction (p &gt, 0.05) between the genetic group and ambient temperature was observed for any performance trait. Irrespective of ambient temperature, Piau crossbred pigs had a similar feed intake (ADFI, 2615 g/day, on average, p &gt, 0.05), lower daily weight gain (ADG, −234 g/day, p &lt, 0.01), and a higher feed conversion ratio (FCR, +0.675 g/g, 0.01). There was interaction (p = 0.01) between genotype and ambient temperature for the LEA that decreased significantly in response to HT in commercial pigs (−6.88 cm2) and did not differ in response to ambient temperature in Piau crossbred pigs (29.14 cm2, on average, 0.05). Piau crossbred pigs had greater BF (+7.2 mm, 0.01) than commercial pigs. Regardless of the genetic group, exposure of pigs to HT resulted in decreased ADFI (−372 g/day, 0.01), ADG (−185 g/day, 0.01), and a higher FCR (+0.48 g/g, p = 0.01). Ambient temperature did not affect lipid deposition. Pigs at HT had an increased respiratory rate (+38 bpm, 0.01) and a long-lasting increase in skin and rectal temperatures compared to TN pigs. Total concentrations of triiodothyronine (T3) and thyroxine (T4) were not affected by ambient temperature in commercial pigs, whereas Piau crossbred pigs kept at 30 °C had a transient decrease in both hormones at day 2 (p &lt, 0.01). Serum cortisol concentrations were not affected (p &gt, 0.05) by genotype nor ambient temperature. In summary, Piau crossbred pigs had lower efficiency using nutrients for growth in association with increased lipid deposition when compared to commercial pigs. In response to HT, commercial pigs had a decreased LEA, whereas no effect was observed for Piau crossbred pigs. Apart from that, commercial and Piau crossbred pigs had a similar magnitude of thermoregulatory responses activation in response to HT, evidencing their innate survival-oriented function.

Made available in DSpace on 2022-05-01T08:45:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Macauba (Acrocomia aculeata) is an oleaginous palm native to tropical America that has received increased attention from the biofuel, food, cosmetic and pharmaceutical industries due to its high productivity and oil quality. Concomitantly, studies have suggested the potential use of macauba coproducts in ruminant feeding with still scarce information on their use in pig feeding and nutrition. The aim of this study was, therefore, to evaluate the effect of dietary macauba pulp meal on growth performance and body composition of growing pigs. To accomplish the goal, a total of 64 barrows, with 30.2 ± 1.5 kg of initial body weight (BW), were assigned to one of the four experimental diets that consisted of corn and soybean-meal based diets formulated with 0, 50, 100 or 150 g/kg of macauba pulp meal inclusion. Diets were formulated with similar metabolizable energy (ME) and crude protein (CP) content. The experimental period lasted 35 days and the pigs had free access to feed and water. Feed intake (FI) was measured and the pigs were weighed at the beginning and end of the trial to calculate their average daily gain (ADG) and feed conversion (FC). Total body minerals, fat and lean content of the pigs were assessed by dual-energy X-ray absorptiometry at the beginning and at the end of the experimental period. Data were analyzed using the GLM procedure of SAS including the fixed effects of diet and initial BW as covariate. Pigs fed with dietary inclusion of 150 g/kg of macauba pulp meal had lower FI than those fed with 0 and 50 g/kg (1,966 vs. 2,097 g/d; P< 0.01). However, macauba pulp meal inclusion did not affect ADG nor FC. Additionally, pigs fed with 150 g/kg of macauba pulp meal in the diet had greater backfat thickness than those with decreased macauba inclusion levels in the diet (P= 0.04). According to our results, macauba pulp meal could be considered as an alternative raw material to be used in the diets of growing pigs. However, its inclusion might result in animals with increased backfat thickness for the higher inclusion rates. Universidade Federal dos Vales do Jequitinhonha e Mucuri Department of Animal Science São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences Universidade Federal de Viçosa Department of Animal Science Topigs Norsvin Research Center, 6641 SZ Beuningen Topigs Norsvin Wageningen University & Research Animal Breeding & Genomics, PO Box 338, 6700 AH São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences CAPES: 001

The study of how different breeds adapt to heat stress and the further understanding of mechanisms underlying pigs thermotolerance is of utmost importance to attenuate the negative effects of heat stress on pigs welfare, physiology, and performance. Therefore, this study aimed at evaluating the effects of ambient temperature on performance and thermoregulatory responses of Piau purebred pigs. The Brazilian native pig breed Piau is a fat-type breed characterized by adaptability and resistance to diseases. To achieve our goal, Piau purebred pigs (65 kg initial BW) were allocated to one of the two constant ambient temperature conditions: thermoneutral (22 °C; n = 11) and heat stress (30 °C; n = 11). The experimental period lasted 15 days (days 1 to 15). Pigs were individually weighed at the beginning and end of the experimental period. Body and rectal temperatures, respiratory rate and blood indicators of stress and metabolism were measured throughout the experiment. Piau purebred pigs exposed to 30 °C had lower (p 0.05) feed intake, body weight gain and final body weight than pigs at 22 °C. Feed conversion rate was not affected (p 0.05) by ambient temperature. Irrespective of ambient temperature, pigs had similar (p 0.05) backfat thickness and loin eye area. Piau pigs at 30 °C had increased (p 0.05) nape, dorsal, flank, and rectal temperatures and increased respiratory rate than their counterparts reared at 22 °C. In summary, our results show that Piau purebred pigs acclimation to 30 °C of ambient temperature is characterized by increased body skin temperature to optimize sensible heat loss to the environment; increased respiratory rate to promote latent heat loss; and by a concomitant reduced voluntary feed intake to reduce heat production associated with digestion and metabolic processes with negative effects on body weight gain.

Made available in DSpace on 2021-06-25T11:04:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Intensification of pig production in developing countries has resulted in increased number of animals per unit area leading to welfare and growth performance issues. This study was then performed to evaluate the effects of space allowance and dietary energy and amino acid content on growth performance and physiological parameters of piglets reared under tropical conditions. A total of 1280 piglets (castrated males and females) with initial body weight of 5.9 ± 0.4 kg were used. Animals were distributed in a 2 × 2 factorial arrangement composed by two space allowances (0.30 and 0.22 m2/animal) and two diets during 43 to 63 days of age (control and experimental diet with increased ME and AA content). The experimental period lasted 42 days subdivided into four phases according to the growth stage of the animals: pre-initial I (21 to 27 days of age), pre-initial II (28 to 34 days), initial I (35 to 42 days), and initial II (43 to 63 days). During pre-initial I and II, and initial I phases, pigs housed at a space allowance of 0.30 and 22 m2/animal had similar (P > 0.05) feed intake, weight gain, and feed conversion. During initial phase II, space allowance did not affect (P > 0.05) feed intake nor weight gain of the animals. Whereas, pigs fed the experimental diet had greater weight gain when compared to the control group (530 vs. 515 g/day, P = 0.03). According to our results, reducing space allowance from 0.30 to 22 m2/animal during the nursery phase (21 to 63 days of age) had negligible effects on piglet feed intake and weight gain, whereas feeding piglets with diets containing higher energy and amino levels resulted in greater weight gain. Animal Science Postgraduate Program Department of Animal Science Universidade Federal dos Vales do Jequitinhonha e Mucuri School of Agricultural and Veterinarian Sciences São Paulo State University (Unesp) Department of Animal Science Universidade Federal de Viçosa Instituto Federal de Educação Ciência e Tecnologia de Minas Gerais AGROCERES PIC School of Agricultural and Veterinarian Sciences São Paulo State University (Unesp) FAPESP: 2018/15559-7