Behaviour of certain productive characteristics, stress and resistance to Salmonella enteritidis in semi-heavy poultry under two production systems

Abstract

WITH THE GOAL OF EVALUATING PRODUCTIVE PARAMETERS, MEASURING STRESS AND ANALYZING RESISTANCE AGAINST SALMONELLA ENTERITIDIS UNDER TWO EGG PRODUCTION SYSTEMS, AN EXPERIMENT ON LAYING HENS WAS PERFORMED. THREE HUNDRED AND SIXTY, 24-WEEK-OLD, RED, LAYER HENS WERE USED. THE BIRDS WERE RANDOMLY ASSIGNED INTO TWO TREATMENTS OF 180 BIRDS EACH. TREATMENTS INCLUDED 4 REPLICATES OF 45 BIRDS DISTRIBUTED AS FOLLOWS: TREATMENT 1, BIRDS HOUSED IN CONVENTIONAL CAGES; AND TREATMENT 2, HOUSED IN PENS WITH ACCESS TO GREEN AREAS. RESULTS AT 53 WEEKS FOR BODY WEIGHT, DAILY FEED CONSUMPTION AND FEED CONVERSION SHOWED NO SIGNIFICANT DIFFERENCE (P > 0.05) BETWEEN TREATMENTS. HOWEVER, FOR TREATMENTS 1 AND 2 RESPECTIVELY, EGG PRODUCTION PERCENTAGE (77.2 ± 0.73 AND 80.1 ± 0.71), EGG WEIGHT (59.24 G ± 0.39 G AND 60.4 G ± 0.44 G), SHELL THICKNESS (0.331 ± 0.0084 MM AND 0.344 ± 0.0008 MM), EGG YOLK COLOR USING A ROCHE YOLK COLOR FAN (8.53 ± 0.080 AND 9.66 ± 0.101), HAUGH UNITS (88.48 ± 0.381 AND 95.34 ± 0.275), HETEROPHILS PER ML (44 874 ± 1 221.73/ML AND 19 400 ± 768.11 / ML), AND LYMPHOCYTES PER ML (29 347 ± 1 068.55/ML AND 51 863 ± 1 511.14/ML) SHOWED STATISTICAL DIFFERENCES, WITH BETTER RESULTS FOR TREATMENT 2 (P < 0.05). SALMONELLA ENTERITIDIS, ISOLATED FROM INTERNAL ORGANS, SHOWED NO STATISTICAL DIFFERENCE BETWEEN TREATMENTS. ADDITIONALLY, YOLK FATTY ACIDS WERE MEASURED, THERE WAS NO STATISTICAL DIFFERENCE, FOR TOTAL FATTY ACIDS (20.02 ± 1.07 AND 24.22 ± 1.00 MG/G OF LIPIDS), HOWEVER TREATMENT 2 WAS SIGNIFICANTLY (P < 0.05) HIGHER FOR LINOLENIC ACID (1.72 ± 0.108 AND 2.19 ± 0.95 MG/G OF LIPIDS) AND DOCOSAHEXAENOIC ACID (3.10 ± 0.161 AND 3.89 ± 0.166 MG/G OF LIPIDS). IT CAN BE CONCLUDED THAT A SEMI-FREEDOM SYSTEM IS ABLE TO REDUCE STRESS, THUS IMPROVING PARAMETERS, AS WELL AS PRODUCE EGGS WITH HIGHER AMOUNTS OF OMEGA 3 FATTY ACIDS.