Efeito do início da fotoestimulação em reprodutoras de codornas de corte de quatro linhagens

Abstract

The experiment aimed to evaluate the effects of the onset of light stimulation in meat quailbreeders of four strains on sexual maturity, productive performance, and egg quality. A totalof 336 female and 112 male meat quails were used for breeding, 84 females and 28 malesfrom each strain. At 35 days of age, the birds were weighed and based on body weight,distributed in a completely randomized design in a 2 x 4 factorial scheme (twophotostimulation programs and four strains), totaling 8 treatments, in which 7 replicates weredistributed. The experimental unit consisted of 6 females and 2 males. The photostimulationprograms consisted of: P1 – photostimulation of the birds at 35 days of age; and P2 –photostimulation of the birds when they reached 50% laying. In both programs, the lightstimulus consisted of offering the birds 14 hours of light per day (natural + artificial) and,subsequently, weekly additions of 30 minutes of artificial light were made until reaching 15hours and 30 minutes of light (natural + artificial), maintaining this amount of daily light untilthe end of the experimental period. From 7 to 37 weeks of age, the following productiveperformance were evaluated: egg production (%/bird/day), feed intake (g/bird/day), eggweight (g), egg mass (g/bird/day), and feed conversion (g/g); egg quality: percentage ofalbumen, yolk, and white, Haugh units, and shell thickness. Statistical analysis of the data wasperformed using analysis of variance and comparison of means using Tukey's test (5%). Therewas no significant interaction between the factors studied and the variables evaluated duringthe experiment. Photostimulation at 35 days of age significantly reduced the age of the birdsat first egg production and at 50% laying, with lineage 1 being the earliest at these ages.During the laying phase, it was observed that feed intake, laying percentage, egg weight, feedconversion, and total number of eggs produced were not significantly influenced by theinitiation of photostimulation of the quails. However, significant differences were observedbetween the lines in terms of egg-laying percentage, total eggs produced, and feed conversion.Birds from lines 1 and 2 had higher egg production and better feed conversion than birds fromlines 3 and 4. Egg quality did not vary significantly according to the age of photostimulationor between strains. It is concluded that photostimulation of breeding quails can be performedat 35 days of age, resulting in early laying without compromising egg production or the sizeand quality of hatching eggs. The strains evaluated responded similarly to light stimulation,with strain 1 being the earliest, and together with strain 2, they were more productive thanstrains 3 and 4.