Nowadays, natural sources of sex reversal agents are preferred over synthetic ones in fish farming due to their reliability and economic value. This study compared the effectiveness of 17α-methyltestosterone (MT), Ca...Nowadays, natural sources of sex reversal agents are preferred over synthetic ones in fish farming due to their reliability and economic value. This study compared the effectiveness of 17α-methyltestosterone (MT), Carica papaya seed meal (PSM), and common carp testes (CCT) with tilapia (Oreochromis niloticus) in terms of sex reversal, hematological parameters, gonadal histology, enzymatic activity, and overall growth. A 90-day trial was conducted with 560 tilapia fry (2- 3 days old) distributed into one control and six treatment aquaria, each with two replicates. Fries were fed with a control diet (T0) or one of six experimental diets (T1-T6) containing different MT, PSM, or CCT levels for 30 days, followed by the control diet for 60 days. MT induced the highest male proportion (85% and 75% in T2 and T1, respectively), while PSM and CCT enhanced tilapia’s growth and carcass composition. Histological analysis revealed gonadal deformities in MT and PSM treatments, which might lead to sterility. The gonadosomatic index (GSI) was reduced in natural treatments as compared with synthetic ones. Hematological parameters did not show any adverse effects of PSM and CCT. Protease and amylase activities were higher in PSM and CCT than in MT, indicating better digestion and feed absorption. PSM and CCT are biodegradable, locally available, and eco-friendly alternatives to synthetic hormones to change sex in tilapia. Natural sources (plant and animal by-products) are preferable to synthetic sources as they are less expensive and control prolific breeding in tilapia.展开更多
Natural hybridization frequently occurs in plants and can facilitate gene flow between species, possibly resulting in species refusion. However, various reproductive barriers block the formation of hybrids and maintai...Natural hybridization frequently occurs in plants and can facilitate gene flow between species, possibly resulting in species refusion. However, various reproductive barriers block the formation of hybrids and maintain species integrity. Here, we conducted a field survey to examine natural hybridization and reproductive isolation （RI） between sympatric populations of Primula secundiflora and P. poissonii using ten nuclear simple sequence repeat （SSR） loci. Although introgressive hybridization occurred, species boundaries between P. secundiflora and P. poissonii were maintained through nearly complete reproductive isolation. These interfertite species provide an excellent model for studying the RI mechanisms and evolutionary forces that maintain species boundaries.展开更多
基金funded by Pakistan Science Foundation (PSF) Project (Grant No. PSF/CRP/GCUF-P/CONSRM-27)The ethics committee of the Government College University Faisalabad, Pakistan approved the animal study protocol for scientific purposes (Approval No. GCUF/ERC/4191).
文摘Nowadays, natural sources of sex reversal agents are preferred over synthetic ones in fish farming due to their reliability and economic value. This study compared the effectiveness of 17α-methyltestosterone (MT), Carica papaya seed meal (PSM), and common carp testes (CCT) with tilapia (Oreochromis niloticus) in terms of sex reversal, hematological parameters, gonadal histology, enzymatic activity, and overall growth. A 90-day trial was conducted with 560 tilapia fry (2- 3 days old) distributed into one control and six treatment aquaria, each with two replicates. Fries were fed with a control diet (T0) or one of six experimental diets (T1-T6) containing different MT, PSM, or CCT levels for 30 days, followed by the control diet for 60 days. MT induced the highest male proportion (85% and 75% in T2 and T1, respectively), while PSM and CCT enhanced tilapia’s growth and carcass composition. Histological analysis revealed gonadal deformities in MT and PSM treatments, which might lead to sterility. The gonadosomatic index (GSI) was reduced in natural treatments as compared with synthetic ones. Hematological parameters did not show any adverse effects of PSM and CCT. Protease and amylase activities were higher in PSM and CCT than in MT, indicating better digestion and feed absorption. PSM and CCT are biodegradable, locally available, and eco-friendly alternatives to synthetic hormones to change sex in tilapia. Natural sources (plant and animal by-products) are preferable to synthetic sources as they are less expensive and control prolific breeding in tilapia.
基金supported by the National Natural Science Foundation of China(31500194 and U1202261)
文摘Natural hybridization frequently occurs in plants and can facilitate gene flow between species, possibly resulting in species refusion. However, various reproductive barriers block the formation of hybrids and maintain species integrity. Here, we conducted a field survey to examine natural hybridization and reproductive isolation （RI） between sympatric populations of Primula secundiflora and P. poissonii using ten nuclear simple sequence repeat （SSR） loci. Although introgressive hybridization occurred, species boundaries between P. secundiflora and P. poissonii were maintained through nearly complete reproductive isolation. These interfertite species provide an excellent model for studying the RI mechanisms and evolutionary forces that maintain species boundaries.
