In culture of the American bullfrog Lithobates catesbeiana, photoperiod is a crucial factor affecting productivity success. Here, the objective was to determine the effect of three photoperiods (high light [HL] = 12 h light [L] : 12 h dark [D]; medium light [ML] = 10 h L : 14 h D; low light [LL] = 8 h L : 16 h D) with different application times on the performance of bullfrog tadpoles. Tadpoles at Gosner stage 25 were subjected to seven different treatments: the HL photoperiod for 90 d (HL90; control); ML for 45 d followed by HL for 45 d (ML45–HL45); LL for 45 d followed by HL for 45 d (LL45–HL45); ML for 60 d followed by HL for 30 d (ML60–HL30); LL for 60 d followed by HL for 30 d (LL60–HL30); LL for 30 d followed by ML and HL, each for 30 d (LL30–ML30–HL30); and ML for 30 d followed by LL and HL, each for 30 d (ML30–LL30–HL30). Response variables included growth, survival rate, feed conversion ratio, protein efficiency ratio, and metamorphosis rate. Likewise, the concentrations of thyroid hormones were established as explanatory variables. The results suggested that by implementing the ML60–HL30 treatment, a higher productive performance was obtained (growth [mean ± SD] = 7,318 ± 0.01 g; survival = 89.33 ± 1.7%; metamorphosis rate = 92.7 ± 1.1%) in relation to HL90 (growth = 7,027 ± 0.02 g; survival = 81.67 ± 2.05%; metamorphosis rate = 90.4 ± 1.7%). The information allows consideration of changes in bullfrog culture, establishing management plans inherent to the exposure times of the different photoperiods in order to obtain the highest performance.

中文翻译：

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美国牛蛙蝌蚪阶段光周期变化：对生长和变态的影响

在美国牛蛙Lithobates catesbeiana 的文化中，光周期是影响生产力成功的关键因素。在这里，目的是确定三个光周期的影响（高光 [HL] = 12 小时光 [L]：12 小时暗 [D]；中光 [ML] = 10 小时 L：14 小时 D；低光 [ LL] = 8 h L : 16 h D) 不同施用时间对牛蛙蝌蚪性能的影响。Gosner 25 期的蝌蚪接受了七种不同的处理：HL 光周期 90 天（HL90；对照）；ML 45 天，然后是 HL 45 天（ML45-HL45）；LL 45 天，然后是 HL 45 天（LL45–HL45）；ML 60 天，然后 HL 30 天（ML60-HL30）；LL 60 天，然后 HL 30 天（LL60-HL30）；LL 30 d，然后是ML和HL，各30 d（LL30-ML30-HL30）；和 ML 30 天，然后是 LL 和 HL，各 30 天（ML30–LL30–HL30）。响应变量包括生长、存活率、饲料转化率、蛋白质效率比和变态率。同样，甲状腺激素的浓度被确定为解释变量。结果表明，通过实施 ML60-HL30 处理，获得了与 HL90 相关的更高生产性能（生长 [平均值±SD] = 7,318 ± 0.01 g；存活率 = 89.33 ± 1.7%；变态率 = 92.7 ± 1.1%） （生长 = 7,027 ± 0.02 g；存活率 = 81.67 ± 2.05%；变态率 = 90.4 ± 1.7%）。该信息允许考虑牛蛙养殖的变化，制定不同光周期暴露时间固有的管理计划，以获得最高性能。结果表明，通过实施 ML60-HL30 处理，获得了与 HL90 相关的更高生产性能（生长 [平均值±SD] = 7,318 ± 0.01 g；存活率 = 89.33 ± 1.7%；变态率 = 92.7 ± 1.1%） （生长 = 7,027 ± 0.02 g；存活率 = 81.67 ± 2.05%；变态率 = 90.4 ± 1.7%）。该信息允许考虑牛蛙养殖的变化，制定不同光周期暴露时间固有的管理计划，以获得最高性能。结果表明，通过实施 ML60-HL30 处理，获得了与 HL90 相关的更高生产性能（生长 [平均值±SD] = 7,318 ± 0.01 g；存活率 = 89.33 ± 1.7%；变态率 = 92.7 ± 1.1%） （生长 = 7,027 ± 0.02 g；存活率 = 81.67 ± 2.05%；变态率 = 90.4 ± 1.7%）。该信息允许考虑牛蛙养殖的变化，制定不同光周期暴露时间固有的管理计划，以获得最高性能。