Impact of Different Levels of Crude Protein on Production Performance and Meat Quality in Broiler Selected for Slow Growth

The production performance and meat quality of the slow-growing hybrid Hubbard JA757 were monitored under conditions of diets differentiated by crude protein content. A total of 1200 as-hatched day-old chickens were equally and randomly allotted into two treatments (T-1 and T-2), with six replicates provided for each treatment (100 chickens/replicate). T-1 chickens received standard diets (according to Hubbard Company recommendations), and those in T-2 were fed diets supplemented with crude protein (+0.5% CP in the growing phase and +1.0% CP in the finishing phase). At the end of the investigations (age 56 days), the T-2 chickens performed better than the T-1 chickens for growth traits (+2.72% body weight; +2.77% daily growth gain; -0.34% mortality; and -4.15% feed conversion ratio); for slaughtering (+0.66% dressed yield; +1.10% breast weight; and +1.25% thigh weight); and for quality meat (+0.55% dry matter in thigh muscles and +1.52% dry matter in breast muscles) (p > 0.05). Statistically significant differences (p < 0.05) occurred between treatments for body weight, daily weight gain, and feed conversion ratio due to the 0.5% CP feed supplementation during the 15-28 day age period, justifying the usefulness of the CP increasing throughout the grower diet only and not during the finishing period.

Automated summary

The production performance and meat quality of slow-growing hybrid chickens were monitored under different diets with varied protein content. The chickens fed with diets supplemented with crude protein showed better growth, slaughtering traits, and meat quality compared to those fed with standard diets.