Fluctuating ambient temperature for weaned pigs: effects on performance and immunological and endocrinological functions.
Following weaning at 3 wk of age, crossbred barrows and gilts were housed in temperature-controlled rooms for a 5-d adjustment period at 35 degrees C, then assigned to receive constant ambient temperature (CT) or fluctuating ambient temperature (FT) treatment for the nursery phase of the experiment. Pigs in FT received 12 h at 35 degrees C and 12 h at 15 degrees C daily for the initial 2 wk of the experiment, then 12 h at 29 degrees C and 12 h at 9 degrees C daily for the final 2 wk. Pigs in CT received 35 degrees C and 29 degrees C continuously for the first and final 2 wk, respectively. Weekly growth performance, feed intake and feed-conversion efficiency were not affected by treatment. Plasma glucose, serum cortisol, monocyte phagocytic function and antibody response to a commercial E. coli bacterin were similar in pigs exposed to CT and FT treatments. Concentrations of insulin in serum were similar between treatments at 0, 1 and 3 wk but were increased for pigs in FT at 2 (P less than .05) and 4 wk (P less than .01). Numbers of lymphocytes, band neutrophils and monocytes in pigs were not influenced by ambient temperature treatment. However, numbers of mature neutrophils for pigs in FT were increased (P less than .05) at 1 and 3 wk of treatment. Eosinophils were also elevated in FT pigs at 4 wk of treatment. Pairs of littermate pigs that had been given CT and FT treatments were selected randomly to continue on the finishing phase of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)
Minton
J E
JE
Kansas State University, Manhattan 66506.
Nichols
D A
DA
Blecha
F
F
Westerman
R B
RB
Phillips
R M
RM
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D004926:Escherichia coli / Q000276:immunology; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D007958:Leukocyte Count / Q000662:veterinary; D008297:Male; D009000:Monocytes / Q000502:physiology; D010587:Phagocytosis; D013552:Swine / Q000276:immunology* / Q000502:physiology*; D013696:Temperature; D014886:Weaning
D000907:Antibodies, Bacterial; D001786:Blood Glucose; D007328:Insulin; D006854:Hydrocortisone