Poultry is the major sources of foodborne salmonellosis. Antibiotic resistance and a surge in zoonotic diseases warrant the use of natural alternatives. Glucosinolates (
GLs
) are naturally occurring antimicrobial compounds in rapeseed and canola. This study investigated the effect of feeding rapeseed, canola meal, and allyl isothiocyanate (
AITC
;
Brassica
secondary metabolites) on growth performance (
GP
), gut health, and the potential antimicrobial activity against nalidixic acid-resistant
Salmonella
Typhimurium (ST
NR
) in chickens. A total of 640 one-day-old male Cobb 500 broilers were randomly allocated to 8 treatments with 8 replicated cages and 10 birds per cage. Dietary treatments were nonchallenge control (
NC
, corn-SBM based), challenge (
Salmonella
) control (
CC
), 10% rapeseed (10RS), 30% rapeseed (30RS), 20% canola meal (20CLM), 40% canola meal (40CLM), 500 ppm AITC (500AITC), and 1,500 ppm AITC (1500AITC). On d 1, all the birds except NC were orally challenged with ST
NR
(7 log CFU/bird). The chickens were reared for 21 d, and their FI and BW were recorded weekly.
Salmonella
cecal colonization and fecal shedding were quantified, whereas organ translocation (OT) of ST
NR
to the spleen, liver, and kidney was tested on 0, 3, 6, 13, and 20-d postchallenge (dpc). Data were subjected to one-way ANOVA, and the means were separated by Duncan's test, except mortality and OT data analyzed after transformation by square root of (n +1) (
P
< 0.05). Overall, feeding 30RS resulted in reduced BW (
P
= 0.003), BWG (
P
= 0.003), and FI (
P
= 0.001) compared to CC, 500AITC, and 1500AITC. Similarly, feeding 20CLM resulted in lower BW and BWG compared to CC (
P
< 0.05) and increased FCR compared to 1500AITC (
P
= 0.03). Feeding CC resulted in higher mortality compared to NC and 30RS (
P
= 0.03). Cecal colonization of ST
NR
was reduced (
P
< 0.0001) for 30RS on 6 dpc and 500AITC on 6 and 13 dpc (
P
< 0.0001). Although no difference in gut permeability was observed 6 dpc (
P
> 0.05), OT of ST
NR
population was the highest for CC in the spleen (
P
= 0.05). In the liver, 10RS showed reduced OT compared to 20CLM on 13 dpc (
P
= 0.03), whereas 30RS showed the lowest OT on 6 dpc in the kidney. Fecal shedding was lowest for 30RS on 6 dpc (
P
= 0.004). Histomorphology showed 30RS had the highest duodenum (
P
= 0.01) and jejunum (
P
= 0.02) villus height (
...