Table 3.

Treatment effect for weight of immune tissues and yolk weight relative to body weight of broilers in ovo inoculated with different concentrations of GalliPro Hatch (GH) Enterococcus faecium–based probiotic on day 18 of incubation: MV alone (Marek's vaccine with not addition of probiotic), 10⁵ cfu GH (MV + 10⁵ cfu GH/50 μL), 10⁶ cfu GH (MV + 10⁶ cfu GH/50 μL), 10⁷ cfu GH (MV + 10⁷ cfu GH/50 μL).¹

Tissue (%)	MV alone	105 cfu GH	106 cfu GH	107 cfu GH	P value	SEM
Yolk on D 02	10.55a	6.408b	6.558b	6.281b	0.0003	0.6957
Spleen	0.093b	0.113a	0.099a,b	0.113a	0.013	0.0048
Bursa	0.13	0.135	0.261	0.154	0.448	0.0646

For each tissue, means in a row not sharing a common superscript are different (P ≤ 0.05).

¹Means are calculated from 10 replicate values using one randomly chosen bird per pen and each pen as the experimental unit (10 pens/treatment,16 birds/pen; 160 total birds/treatment).

²Yolk weight obtained only on D 0. No egg yolk was present for most of the replication units during the remaining days of the grow-out cycle. Spleen and bursa weighed obtained on D 0, 7,14, and 21.