10 important days in the life of a broiler

Why does an efficient starter diet during the first 10 days make a difference to broiler performance throughout the production lifecycle? A feeding trial at the University of New England, Australia, has investigated the carry-over effect of HP AviStart from Hamlet Protein on broiler digestive systems.

Katia Pedrosa. Photo: Hamlet Protein

HP AviStart is a source of highly digestible soy protein that is low in anti-nutritional factors. For the trial, 2.5%, 5% and 10% doses were added to maize and wheat-based starter diets which were then fed to male Ross 308 birds from day 1 to day 10. The control diets contained no HP AviStart.

The birds were housed in groups of 10, with 6 replicates per treatment.

Regardless of whether broilers received the wheat or maize-based diet, feed conversion rate and carcass yield were both improved if the diet contained HP AviStart. The highest dose of the specialty soy protein gave the lowest FCR compared to the control (Table 1).

Table 1 - Performance from day 1-35 of birds fed increasing levels of HP AviStart during starter period (day 1-10) in a maize or wheat-based diet.

ᵃ˒ᵇ- Mean values with an ᵃ and ᵇ superscript in the same row are significantly different (P<0.05)

	Response	control	HP AviStart (2.5 g/kg)	HP AviStart (5 g/kg)	HP AviStart (10 g/kg)
Maize	Fl (g)	3932	3803	3860	3773
Maize.	BW (g)	2520	2557	2624	2589
Maize,	FCR	1.58ᵃ	1.51ᵇ	1.49ᵇ	1.48ᵇ
Wheat	Fl (g)	3723	3754	3810	3718
Wheat.	BW (g)	2390	2503	2540	2642
Wheat,	FCR	1.59ᵃ	1.52ᵃ	1.52ᵃ	1.43ᵇ

Figure 1 shows that, in the maize-based diet, the greatest improvement in the ileal digestibility of protein was 10% at an addition level of 2.5% HP AviStart. The maximum improvement in the wheat-based diet was 5%, observed in broilers fed the diet with 5% HP AviStart.

Figure 1 - Ileal CP digestibility.

 

Table 2 - Carcass yield and meat part yield of 35-day-old broiler chickens fed increasing levels of HP AviStart during the starter period (day 1-10)

	Response	control	HP AviStart (2.5 g/kg)	HP AviStart (5 g/kg)	HP AviStart (10 g/kg)
Maize	Carcass yield (%)	75	76	76	76
Maize.	Breast (g)	675	714	739	694
Maize,	Thigh (g)	304	334	337	321
Maize.,	Drumstick (g)	243	245	255	238
Wheat	Carcass yield (%)	75	75	76	77
Wheat.	Breast (g)	655	638	704	694
Wheat,	Thigh (g)	295	299	330	323
Wheat.,	Drumstick (g)	235	231	249	241

Improved carcass yield was calculated from breast, thigh and drumstick measurements. Compared to the control group, birds fed a starter diet with HP AviStart had around 10% more breast and thigh meat and 5% higher drumstick yield. The highest yield was obtained with 5% addition of HP AviStart (Table 2).

In broilers fed both the maize and wheat-based diets, villus/crypt ratio increased following a starter diet with HP AviStart and was highest at a 5% addition rate. A strong correlation was observed between villus/crypt ratio and breast meat.

Figure 2 - Carryover effect at day 24 on villus/crypt ratio after feeding HP AviStart in the starter diet (day 1-10).

 

These findings support previous studies of the carryover effect of HP AviStart on broiler performance, gut health and protein digestibility. Improved body weight and feed conversion rate alone point to a high return on investment when HP AviStart is added to broiler starter feed.