Studies on the effect of Lactococcus garvieae of dairy origin on both cheese and Nile tilapia (O. niloticus)

Peer review under responsibility of Faculty of Veterinary Medicine, Cairo University.

Figures & data

able 2 Mortality rates record in pathogenicity experiment with S. aureus and in feeding experiment using L. garvieae.

Experiments	No. of fish	Mortalities within							No of dead fish	Mortality rate %
Pathogenicity experiment with S. aureus		48 h	72 h	96 h	5 days	week	10 Days	2 weeks
Group 1	30	2	3	5	4	5	6	5	30	100%
Group 2	30	0	0	0	0	0	0	0	0	0
Feeding experiment using L. garvieae
Group 1^*	30	0	0	0	0	0	0	0	0	0
Group 2^*	30	0	0	0	0	0	0	0	0	0
Group 3^*	30	2	2	4	3	5	7	4	27	90%
Group 4^*	30	1	3	4	2	3	2	–	15	50%

Group 1, fish inoculated IP with 0.5 mL of L. garvieae, Group 2, fish inoculated IP with 0.5 mL of saline solution, Group 1^* fish fed an ordinary diet, Group 2^*, fish fed a diet containing L. garvieae, Group 3^* fish infected with S. aureus and fed an ordinary diet and Group 4^*, fish infected with S. aureus and fed a diet containing the probiotic bacterium.

ig. 1 Counts of S. aureus in cheese during refrigerated storage over 10 days.

able 1 Counts of S. aureus in cheese during refrigerated storage over 10 days.

Cheeses containing (CFU/g)	Storage time (days)
	0	2	4	6	8	10
(A) Cheese without added L. garvieae that was experimentally contaminated with S. aureus	3.35 ± 0.04	3.35 ± 0.05	3.51 ± 0.02	3.73 ± 0.02	4.77 ± 0.01	5.97 ± 0.06
(B) Cheese containing L. garvieae that was experimentally contaminated with S. aureus	3.66 ± 0.02	3.49 ± 0.04	3.48 ± 0.03	3.53 ± 0.04	3.84 ± 0.02	3.90 ± 0.02
(C) Control cheese that contained no added cultures	<1	<1	<1	<1	<1	<1

able 3 Immunological parameters following the feeding experiment.

Groups	Parameters
	IgM (mg/mL)	Lysozyme (μg/mL)	Nitric Oxide(μg/mL)
Gp. (1)	0.57^b	0.37^b	35.38^b
Gp. (2)	0.96^a	0.66^a	49.60^a
Gp. (3)	0.26^d	0.17^c	20.71^c
Gp. (4)	0.64^b	0.39^b	36.52^b
SEM^1	0.07	0.05	3.08
P value	0.000	0.000	0.000

SEM¹, Standard error of the mean.

Means bearing different superscripts within the same column are significantly different (P < .05). Highest value is represented by the letter (a), followed by the letter (b), then (c) and letter (d) represent the lowest value.

Group (1), control group; Group (2), fish fed a diet containing the probiotic bacterium; Group (3), fish infected with S. aureus, and Group (4), fish infected with S. aureus that were fed a diet containing the probiotic bacterium