Table 1.
Basal Torula yeast-based chick dieta.
Table 2.
qPCR primers for chicken selenoproteinsa.
Fig 1.
Effect of dietary Se on growth and growth rate in chicks.
A. Body weights of day-old male chicks supplemented with graded levels of dietary Se at the indicated levels for 29 d (n = 5/treatment) and weighed biweekly. Values are the mean weight±SEM. Means at day 29 without a common letter are significantly different (P<0.05). B. Daily weight gain of chicks over days 14–29, calculated as g/day. Hyperbolic line is the resulting Se response curve with a breakpoint (BP) of 0.028 μg Se/g diet, calculated as described in the text. Means without a common letter are significantly different (P<0.05).
Table 3.
Se requirement hierarchy in growing chicks.
Fig 2.
Effect of dietary Se on selenoenzyme activity.
Activities for plasma GPX3 (A), RBC GPX1 (B), liver GPX1 (C), liver GPX4 (D), gizzard GPX1 (E), gizzard GPX4 (F), pancreas GPX1 (G), and pancreas GPX4 (H) in chicks supplemented with the indicated graded levels of dietary Se for 29 d. Activities are expressed as enzyme unit (EU)/g protein. Values are the mean±SEM (5/treatment). Means without a common letter are significantly different (P<0.05). Overall level of significance, as determined by ANOVA, is given in Table 3. Se response curve breakpoints (BP) are indicated in each panel, calculated as described in the text.
Fig 3.
Relative expression of selenoprotein transcripts in Se-adequate chick liver (A), gizzard (B) and pancreas (C). Relative transcript expression for each gene was determined by qPCR and expressed relative to the level of GPX1 transcript, as described in the text. Se-adequate tissues were from chicks fed 0.3 mg Se/g diet. Primer pairs used for these analyses are listed in Table 2. Bars show the mean±SEM (n = 4).
Fig 4.
Effect of Se status on relative expression of selenoprotein transcripts in chick liver (A), gizzard (B) and pancreas (C). Liver and gizzard RNA was from chicks supplemented with 0, 0.3, or 1.0 μg Se/g diet. Pancreas RNA was from chicks supplemented with 0, 0.025, 0.3, or 1.0 μg Se/g diet. Relative transcript expression for each gene was determined by qPCR and expressed relative to the level in Se-adequate (0.3 μg Se/g diet) Bars show the mean±SEM (n = 4). Asterisks indicated significant effects of dietary treatment (P<0.05).
Fig 5.
Effect of dietary Se on significantly-regulated selenoprotein transcript level in chick liver.
Relative transcript levels are plotted for GPX1 (A), GPX3 (B), GPX4 (C), DIO1 (D), SELH (E), SELM (F), SELU (G) and SEPP1 (H) in chicks supplemented with the indicated levels of dietary Se for 29 d. Values were determined in triplicate for each sample, normalized to the mean of GAPDH and ACTB levels in each sample, expressed as a percentage of Se-adequate plateau levels, and plotted as mean±SEM (n = 4/treatment). Means without a common letter are significantly different (P<0.05). Overall level of significance, as determined by ANOVA, is given in Table 3. Se response curve breakpoints (BP) are indicated in each panel, calculated as described in the text.
Fig 6.
Effect of dietary Se on unregulated selenoprotein transcript levels in chick liver.
Relative transcript levels are plotted for EPT1 (A), SEPN1 (B), SEPP2 (C), SEPHS1 (D), GAPDH (E), ACTB (F), and DIO2 (G) in chicks supplemented with the indicated levels of dietary Se for 29 d. Values were determined in triplicate for each sample, normalized to the mean of GAPDH and ACTB levels in each sample, expressed as a percentage of Se-adequate plateau levels, and plotted as mean±SEM (n = 3-4/treatment). Overall level of significance, as determined by ANOVA, is indicated in each panel.
Fig 7.
Effect of dietary Se on selenoprotein transcript level in chick gizzard.
Relative transcript levels are plotted for GPX1 (A), GPX3 (B), GPX4 (C), SELH (D), SELM (E), SELU (F), SEPN1 (G), and SEPP1 (H) in chicks supplemented with the indicated levels of dietary Se for 29 d. Values were determined in triplicate for each sample, normalized to the mean of GAPDH and ACTB levels in each sample, expressed as a percentage of Se-adequate plateau levels, and plotted as mean±SEM (n = 3-4/treatment). For panels A-F, means without a common letter are significantly different (P<0.05). Overall level of significance, as determined by ANOVA, is given in Table 3. Se response curve breakpoints (BP) are indicated in each panel, calculated as described in the text. For panels G and H, overall level of significance, as determined by ANOVA.
Fig 8.
Effect of dietary Se on significantly-regulated selenoprotein transcript level in chick pancreas.
Relative transcript levels are plotted for MSRB1 (A), SELK (B), VIMP (C), SEPW1 (D), GPX3 (E), GPX4 (F), SEPP1 (G), SEP15 (H), GPX1 (I), SELM (J), SELU (K), and SELH (H) in chicks supplemented with the indicated levels of dietary Se for 29 d. Values were determined in triplicate for each sample, normalized to the mean of GAPDH and ACTB levels in each sample, expressed as a percentage of Se-adequate plateau levels, and plotted as mean±SEM (n = 3-4/treatment). Means without a common letter are significantly different (P<0.05). Overall level of significance, as determined by ANOVA, is given in Table 3. Se response curve breakpoints (BP) are indicated in each panel, calculated as described in the text.
Fig 9.
Effect of dietary Se on transcript panel values in chick liver (A), gizzard (B), and pancreas (C). Within a tissue, the individual relative transcript levels for each significantly-regulated selenoprotein were averaged to calculate panel values, which were then subjected to the Se response curve analysis as described in the text. Resulting mean±SEM are plotted, and means without a common letter are significantly different (P<0.05). Overall level of significance, as determined by ANOVA, is given in Table 3. Se response curve breakpoints (BP) are indicated in each panel, calculated as described in the text.