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A novel product (SQ12) for subcutaneous (SQ) injectable delivery of oxytetracycline (OTC) has been developed for use in livestock. SQ12 employs microfluidic spheres encasing OTC crystals, which allows for longer release of the OTC compared with other injectable antibiotics. The objectives of the study were to determine serum and tissue levels of SQ12 in turkey breeder hens to 14 days postinjection and to evaluate effects of SQ12 on reproductive status. Thirty photostimulated hens were housed in litter floor pens and provided with 14.5 hr of light per day in a curtain-sided facility. Six hens served as untreated controls. Twelve hens per treatment group received SQ injections in the neck with SQ12 at 11.4 (L dose group) or 22.7 mg/kg (H dose group) to assess low and high doses, respectively. Serum samples were obtained from each hen at predose and 6, 12, 24, 48, 72, 96, 168, 240, and 336 hr postinjection. All hens were euthanatized at 14 and 15 days postinjection. One-half of the hens in each treatment group were sampled (liver, lung, kidneys, and breast muscle) for tissue residue levels of OTC. The control group had no detectable OTC in serum or tissues at any sample collection time. There were no detectable serum levels of OTC in either treatment group prior to injection. The average serum concentrations of the L and H dose groups showed similar depletion curves although the H dose group was 42% higher at maximum concentration than the L group. Average tissue concentration of OTC for all tissues sampled from the H dose group was twice that of the L dose group. All tissue levels were below the OTC residue tolerance limit. SQ12 provided an extended source of OTC in serum of turkey breeder hens with no effect on reproductive status. SQ12 may provide for a novel treatment of bacterial infection in turkey breeder hens with longer lasting serum levels compared with other single injectable OTC products.

An experiment was conducted to examine the effects of prebreeder protein intake on subsequent reproductive performance and to examine body weight, feed consumption, and body composition changes due to aging in Large White turkey breeder hens. One hundred twenty-nine Hybrid Large White turkey breeder hens were fed either 12, 15, or 18% CP diets (2,882 kcal ME/kg) during the prebreeder period from 24 to 32 wk of age. All hens were photostimulated with 15.5 h light/day and fed a standard 16% protein breeder ration from 32 to 55 wk of age. Prebreeder protein intake increased linearly as dietary protein increased. Treatments did not affect body weight, body composition, egg production, feed consumption, fertility, hatch of fertile eggs, or percentages of early or late dead. Body weight increased from 24 to 55 wk in a cubic response to age. Percentage of carcass moisture decreased, whereas percentage of carcass fat increased from 24 to 55 wk in a quadratic response to age. Prebreeder and breeder feed consumption were not significantly affected by treatment or age. This experiment is evidence that a 12% protein prebreeder ration is adequate for subsequent reproductive performance; observed effects of age on body characteristics agree with published data.