A novel apidaecin Api-PR19 synergizes with the gut microbial community to maintain intestinal health and promote growth performance of broilers

Table 2 Effects of Api-PR19 and antibiotic on growing performance, immune organ index, and immune function of 21-day-old and 42-day-old broiler chickens

Item	Period/age	Indices	CON	AGP	Api-PR19, mg/kg			SEM	P-value
Item	Period/age	Indices	CON	AGP	100	200	300	SEM	P-value
Growth performance	1–21 d	ADFI, g	54.49	54.28	54.72	54.72	54.13	0.439	0.992
		ADG, g	39.09	39.74	39.99	40.57	39.85	0.325	0.735
		FCR	1.394^a	1.366^ab	1.367^ab	1.349^b	1.359^b	0.005	0.041
	22–42 d	ADFI, g	147.45	152.54	146.29	151.25	150.32	1.815	0.819
		ADG, g	72.58	76.12	71.13	77.28	75.31	1.157	0.442
		FCR	2.033	2.006	2.065	1.959	1.998	0.068	0.070
	1–42 d	ADFI, g	97.16	101.06	97.11	100.21	98.86	1.161	0.786
		ADG, g	53.03	56.62	53.41	57.20	55.65	0.729	0.262
		FCR	1.832^a	1.783b^c	1.820^b	1.753^c	1.775^c	0.008	0.005
Immune organ development	21 d	Thymus index	2.20	2.02	2.22	2.13	2.22	0.081	0.555
		Spleen index	0.88	0.78	0.83	0.67	0.70	0.033	0.338
		Bursa index	2.37^a	1.60^c	1.77^b	1.72^b	2.15^a	0.772	0.025
	42 d	Thymus index	3.24	3.01	3.44	2.70	2.79	0.150	0.519
		Spleen index	0.95	0.90	0.93	0.88	0.83	0.028	0.130
		Bursa index	0.48	0.45	0.52	0.38	0.35	0.031	0.387
IgG	21 d	Serum IgG	386.14	462.21	355.86	340.43	304.71	20.264	0.156
IgG	42 d	Serum IgG	636.86	524.71	732.33	430.90	731.38	44.642	0.158
H₅ & H₉ antibody level (log₂)	7 d	H₅	8.29	7.71	8.14	8.28	8.71	0.771	0.193
	14 d		6.43	5.86	5.71	6.00	6.00	0.797	0.566
	21 d		4.28	3.85	5.00	4.43	4.43	0.743	0.059
	28 d		4.29	3.43	4.14	3.14	3.57	1.269	0.416
	7 d	H₉	9.57^a	8.00^b	9.57^a	9.43^a	10.29^a	1.374	0.024
	14 d		7.29	6.86	6.71	6.43	6.43	1.121	0.612
	21 d		4.43	4.00	4.14	4.43	4.57	0.900	0.775
	28 d		3.57	3.71	2.86	3.29	4.00	1.091	0.363

Note: ADFI average daily feed intake; ADG average daily weight gain; FCR ratio of feed intake to weight gain. ^a-b within a row with different superscripts means significantly difference

ISSN: 2049-1891