Dietary electrolyte balance for broiler chickens exposed to thermoneutral or heat-stress environments.
Ross male broiler chicks (n = 480) on new litter were used in a randomized block design with two blocks (environmental rooms) and four treatments having four replicate pens (1.0 x 2.5 m; 15 chicks) each to evaluate dietary electrolyte balance (DEB; P < 0.05). Two rooms were 1) thermoneutral (Weeks 1 through 6, with decreasing maximum from 32 to 25 degrees C and minimum from 28 to 19 degrees C; relative humidity 49 to 58%) and 2) cyclic daily heat stress (Weeks 1 and 2, thermoneutral; Weeks 2 through 6, maximum temperatures 35, 35, 33, and 33 degrees C, respectively; and minimum temperatures 23, 20, 19, and 19 degrees C, respectively; relative humidity 51 to 54%). The DEB treatments (0, 140, 240, or 340 mEq Na + K - Cl/kg) had NaHCO3 plus NH4Cl, or KHCO3, or both added to corn-soybean meal mash basal diets with 0.30% salt (NaCl). In the thermoneutral room, DEB 240 increased 42-d weight gain and 44-d lymphocyte percentage and decreased heterophil percentage and heterophil to lymphocyte ratio compared to the DEB 40 treatment. The DEB 240 diets had 0.35 and 0.35% Na and 0.37% and 0.29% Cl in starter (0.75% K) and grower (0.67% K) diets, respectively. No DEB treatment differences were found in the heat stress room. For combined rooms, 42-d feed intake was higher for DEB 240 than for DEB 40. The 21-d weight gain was higher for DEB 240 than for DEB 40 or 140; and 21-d feed/gain was lower for DEB 40 than for DEB 340. The predicted maximum point of inflection for 21- and 42-d weight gains were DEB 250 and 201, with highest 42-d feed intake at 220.
Borges
S A
SA
Department of Zootecnia, FCAV/UNESP, Rodovia Carlos Tonanni km 05, Jaboticabal, CEP 14870-000, Sao Paulo, Brazil.
Fischer da Silva
A V
AV
Ariki
J
J
Hooge
D M
DM
Cummings
K R
KR
D000643:Ammonium Chloride / Q000008:administration & dosage; D000818:Animals; D001639:Bicarbonates / Q000008:administration & dosage; D002645:Chickens / Q000502:physiology*; D002712:Chlorides / Q000008:administration & dosage; D004032:Diet; D004435:Eating; D004573:Electrolytes / Q000008:administration & dosage*; D004734:Energy Metabolism; D006358:Hot Temperature; D006813:Humidity; D006863:Hydrogen-Ion Concentration; D008297:Male; D017680:Potassium Compounds / Q000008:administration & dosage; D017419:Potassium, Dietary / Q000008:administration & dosage; D012044:Regression Analysis; D017693:Sodium Bicarbonate / Q000008:administration & dosage; D012982:Sodium, Dietary / Q000008:administration & dosage; D013025:Glycine max; D013312:Stress, Physiological; D015430:Weight Gain; D003313:Zea mays
D001639:Bicarbonates; D002712:Chlorides; D004573:Electrolytes; D017680:Potassium Compounds; D017419:Potassium, Dietary; D012982:Sodium, Dietary; D000643:Ammonium Chloride; D017693:Sodium Bicarbonate; C026329:potassium bicarbonate