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Papers by Stephanie Velasquez

Research paper thumbnail of Serum Biochemical Profile of Captive-bred Philippine Crocodiles (Crocodylus mindorensis Schmidt, 1935) Sub-adults

The Philippine journal of science, May 6, 2021

Total protein (g L-1) Biuret reaction 38.01-195.15 Albumin (g L-1) Bromocresol green 11.85-25.25 ... more Total protein (g L-1) Biuret reaction 38.01-195.15 Albumin (g L-1) Bromocresol green 11.85-25.25 Globulin (g L-1) Equation 24.85-169.90 Cholesterol (mmol L-1) Uricase 2.90-6.19 Uric acid (µmol L-1) Cholesterol esterase 173.84-1256.78 Triglycerides (mmol L-1) Glyceryl-phosphate oxidase 0.53-17.66

Research paper thumbnail of Growth and immune response of pond-reared giant freshwater prawn Macrobrachium rosenbergii post larvae fed diets containing Chlorella vulgaris

Aquaculture and Fisheries, 2020

A 70-day feeding trial was conducted to evaluate the efficacy of Chlorella vulgaris supplementati... more A 70-day feeding trial was conducted to evaluate the efficacy of Chlorella vulgaris supplementation in diets of giant freshwater prawn (Macrobrachium rosenbergii) post larvae. Resistance of the prawns against Aeromonas hydrophila and several immune parameters (total hemocyte count and prophenoloxidase activity) were also assessed in the study. Iso-nitrogenous, iso-lipidic, and iso-caloric prawn feeds were prepared utilizing a fishmeal based positive control diet (F0) and four dietary treatments with C. vulgaris inclusion levels of 2 (F2), 4 (F4), 6 (F6), and 8 (F8) %. Post larvae of M. rosenbergii were stocked randomly (mean initial body weight of 0.39 � 0.38 g) in fifteen net cages (8.1 m � 8.9 m with an average depth of 1 m) in an earthen pond for the assessment of growth parameters. Overall growth indices for prawn fed Chlorella containing diets were enhanced in comparison to the control treatment. Prawn fed diets with Chlorella showed significantly higher (P < 0.05) prophenol oxidase activity, total hemocyte counts, and survival rates post bacterial infection. These findings demonstrated that inclusion of 4%, 6%, and 8% C. vulgaris in prawn diets provided optimal growth rates and improved immunity of the post larvae.

Research paper thumbnail of A review on Spirulina: alternative media for cultivation and nutritive value as an aquafeed

Reviews in Aquaculture, 2020

The nutritional value of spirulina in aquafeeds has been studied extensively as a fishmeal replac... more The nutritional value of spirulina in aquafeeds has been studied extensively as a fishmeal replacer or as a functional feed additive to increase growth and health performance of fish in the last decade. Despite increased interest in spirulina research in aquaculture, its increased production cost still limits its use in commercial rations. Zarrouk's medium is the standard substrate used for growing spirulina. Although this medium offers optimal biomass production, it incurs higher costs due to the expensive components needed for concocting the medium. In this regard, development of cost-effective alternative culture medium or techniques is necessary for the industrial-scale production of these microalgae. This paper reviews research on different alternative media for spirulina cultivation and its nutritive value as an aquafeed. Numerous alterations in the composition of Zarrouk's medium with cheaper chemical ingredients have been explored as a potential substitute for cost-effective microalgae cultivation. Industrial and processing wastes and by-products with appropriate nutrient profiles for growing spirulina are also being considered as alternative culture media. The use of rice bran or other cheaper agricultural by-products, as a cost-effective growth medium for commercial-scale spirulina production has yet to be explored extensively in agriculture-based countries, especially in rice-producing Asian countries.

Research paper thumbnail of Replacement of fishmeal with processed meal from knife fish Chitala ornata in diets of juvenile Nile tilapia Oreochromis niloticus

Aquaculture Reports, 2017

A 60-day feeding trial was conducted to assess the effects of processed meal from knife fish Chit... more A 60-day feeding trial was conducted to assess the effects of processed meal from knife fish Chitala ornata (KFM) as fishmeal replacement in diets of Nile tilapia Oreochromis niloticus juveniles. Five isonitrogenous (36.4% in dry matter) and isolipidic diets (8.6% in dry matter) with 0 (D1), 25 (D2), 50 (D3), 75 (D4) and 100% (D5) KFM inclusions were prepared. With a stocking density of 15 fish (0.59 ± 0.01 g) per tank, tilapia juveniles were distributed randomly in fifteen 30-L tanks. Results indicate a significant increase (P < 0.05) in the percent average weight gain, specific growth rate, and feed intake with increasing KFM inclusion up to the level of 75%. There were no adverse effects observed in both blood profile and carcass composition of the tilapia. Hepatosomatic index of fish significantly increased (P < 0.05) when KFM was included into the diet of tilapia, compared to those fed D1. Viscerosomatic indices were not significantly different (P > 0.05) among treatments. Results of hepatic histopathology showed absence of tumors, lesions and parenchymal inflammation in all treatments. However, mild cell membrane lysis and mild and mild to moderate apoptosis were evident in liver samples. Based on the results, KFM can partially and completely replace dietary protein from fishmeal. Moreover, D4 (75% KFM) is considered the optimal KFM replacement level for Nile tilapia juveniles.

Research paper thumbnail of Dietary Spirulina (Arthrospira platensis) replacement enhances performance of juvenile Nile tilapia (Oreochromis niloticus)

Journal of Applied Phycology, 2015

Research paper thumbnail of Growth and immune response of giant freshwater prawn Macrobrachium rosenbergii (De Man) postlarvae fed diets containing Chlorella vulgaris (Beijerinck)

Aquaculture Research, 2016

A 50-day growth trial was conducted to evaluate the efficacy of Chlorella vulgaris (Beijerinck) a... more A 50-day growth trial was conducted to evaluate the efficacy of Chlorella vulgaris (Beijerinck) as an ingredient in the diets of giant freshwater prawn Macrobrachium rosenbergii (De Man) postlarvae (PL30). Immune response (total haemocyte count and prophenoloxidase activity) was also assessed by subjecting postlarvae to a challenge test against Aeromonas hydrophila (Chester) for 14 days. Isonitrogenous and iso-lipidic test diets were prepared using a fishmeal-based-positive control diet (D0) and four basal diets with inclusion levels of 2% (D2), 4% (D4), 6% (D6) and 8% (D8) C. vulgaris. Postlarvae of M. rosenbergii were randomly stocked (mean initial body weight of 0.19 AE 0.02 g) in 30-L tanks in three replicates per dietary treatment for evaluation of growth performance. Another set of postlarvae (mean initial body weight of 1.25 AE 0.02 g) was randomly distributed in 95-L tanks in three replicates per dietary treatment for the assessment of immune response. Results showed that specific growth rate was significantly higher (P < 0.05) in postlarvae fed D4 and D6. Variations in values for carcass protein, lipid, moisture and ash were also evident. Postlarvae fed diets with Chlorella showed increased prophenol oxidase activity and total haemocyte counts. Moreover, survival rate after challenge with A. hydrophila was significantly increased (P < 0.05). Inclusion of C. vulgaris in diets enhanced immune response and resistance of M. rosenbergii postlarvae against A. hydrophila infection.

Research paper thumbnail of Serum Biochemical Profile of Captive-bred Philippine Crocodiles (Crocodylus mindorensis Schmidt, 1935) Sub-adults

The Philippine journal of science, May 6, 2021

Total protein (g L-1) Biuret reaction 38.01-195.15 Albumin (g L-1) Bromocresol green 11.85-25.25 ... more Total protein (g L-1) Biuret reaction 38.01-195.15 Albumin (g L-1) Bromocresol green 11.85-25.25 Globulin (g L-1) Equation 24.85-169.90 Cholesterol (mmol L-1) Uricase 2.90-6.19 Uric acid (µmol L-1) Cholesterol esterase 173.84-1256.78 Triglycerides (mmol L-1) Glyceryl-phosphate oxidase 0.53-17.66

Research paper thumbnail of Growth and immune response of pond-reared giant freshwater prawn Macrobrachium rosenbergii post larvae fed diets containing Chlorella vulgaris

Aquaculture and Fisheries, 2020

A 70-day feeding trial was conducted to evaluate the efficacy of Chlorella vulgaris supplementati... more A 70-day feeding trial was conducted to evaluate the efficacy of Chlorella vulgaris supplementation in diets of giant freshwater prawn (Macrobrachium rosenbergii) post larvae. Resistance of the prawns against Aeromonas hydrophila and several immune parameters (total hemocyte count and prophenoloxidase activity) were also assessed in the study. Iso-nitrogenous, iso-lipidic, and iso-caloric prawn feeds were prepared utilizing a fishmeal based positive control diet (F0) and four dietary treatments with C. vulgaris inclusion levels of 2 (F2), 4 (F4), 6 (F6), and 8 (F8) %. Post larvae of M. rosenbergii were stocked randomly (mean initial body weight of 0.39 � 0.38 g) in fifteen net cages (8.1 m � 8.9 m with an average depth of 1 m) in an earthen pond for the assessment of growth parameters. Overall growth indices for prawn fed Chlorella containing diets were enhanced in comparison to the control treatment. Prawn fed diets with Chlorella showed significantly higher (P < 0.05) prophenol oxidase activity, total hemocyte counts, and survival rates post bacterial infection. These findings demonstrated that inclusion of 4%, 6%, and 8% C. vulgaris in prawn diets provided optimal growth rates and improved immunity of the post larvae.

Research paper thumbnail of A review on Spirulina: alternative media for cultivation and nutritive value as an aquafeed

Reviews in Aquaculture, 2020

The nutritional value of spirulina in aquafeeds has been studied extensively as a fishmeal replac... more The nutritional value of spirulina in aquafeeds has been studied extensively as a fishmeal replacer or as a functional feed additive to increase growth and health performance of fish in the last decade. Despite increased interest in spirulina research in aquaculture, its increased production cost still limits its use in commercial rations. Zarrouk's medium is the standard substrate used for growing spirulina. Although this medium offers optimal biomass production, it incurs higher costs due to the expensive components needed for concocting the medium. In this regard, development of cost-effective alternative culture medium or techniques is necessary for the industrial-scale production of these microalgae. This paper reviews research on different alternative media for spirulina cultivation and its nutritive value as an aquafeed. Numerous alterations in the composition of Zarrouk's medium with cheaper chemical ingredients have been explored as a potential substitute for cost-effective microalgae cultivation. Industrial and processing wastes and by-products with appropriate nutrient profiles for growing spirulina are also being considered as alternative culture media. The use of rice bran or other cheaper agricultural by-products, as a cost-effective growth medium for commercial-scale spirulina production has yet to be explored extensively in agriculture-based countries, especially in rice-producing Asian countries.

Research paper thumbnail of Replacement of fishmeal with processed meal from knife fish Chitala ornata in diets of juvenile Nile tilapia Oreochromis niloticus

Aquaculture Reports, 2017

A 60-day feeding trial was conducted to assess the effects of processed meal from knife fish Chit... more A 60-day feeding trial was conducted to assess the effects of processed meal from knife fish Chitala ornata (KFM) as fishmeal replacement in diets of Nile tilapia Oreochromis niloticus juveniles. Five isonitrogenous (36.4% in dry matter) and isolipidic diets (8.6% in dry matter) with 0 (D1), 25 (D2), 50 (D3), 75 (D4) and 100% (D5) KFM inclusions were prepared. With a stocking density of 15 fish (0.59 ± 0.01 g) per tank, tilapia juveniles were distributed randomly in fifteen 30-L tanks. Results indicate a significant increase (P < 0.05) in the percent average weight gain, specific growth rate, and feed intake with increasing KFM inclusion up to the level of 75%. There were no adverse effects observed in both blood profile and carcass composition of the tilapia. Hepatosomatic index of fish significantly increased (P < 0.05) when KFM was included into the diet of tilapia, compared to those fed D1. Viscerosomatic indices were not significantly different (P > 0.05) among treatments. Results of hepatic histopathology showed absence of tumors, lesions and parenchymal inflammation in all treatments. However, mild cell membrane lysis and mild and mild to moderate apoptosis were evident in liver samples. Based on the results, KFM can partially and completely replace dietary protein from fishmeal. Moreover, D4 (75% KFM) is considered the optimal KFM replacement level for Nile tilapia juveniles.

Research paper thumbnail of Dietary Spirulina (Arthrospira platensis) replacement enhances performance of juvenile Nile tilapia (Oreochromis niloticus)

Journal of Applied Phycology, 2015

Research paper thumbnail of Growth and immune response of giant freshwater prawn Macrobrachium rosenbergii (De Man) postlarvae fed diets containing Chlorella vulgaris (Beijerinck)

Aquaculture Research, 2016

A 50-day growth trial was conducted to evaluate the efficacy of Chlorella vulgaris (Beijerinck) a... more A 50-day growth trial was conducted to evaluate the efficacy of Chlorella vulgaris (Beijerinck) as an ingredient in the diets of giant freshwater prawn Macrobrachium rosenbergii (De Man) postlarvae (PL30). Immune response (total haemocyte count and prophenoloxidase activity) was also assessed by subjecting postlarvae to a challenge test against Aeromonas hydrophila (Chester) for 14 days. Isonitrogenous and iso-lipidic test diets were prepared using a fishmeal-based-positive control diet (D0) and four basal diets with inclusion levels of 2% (D2), 4% (D4), 6% (D6) and 8% (D8) C. vulgaris. Postlarvae of M. rosenbergii were randomly stocked (mean initial body weight of 0.19 AE 0.02 g) in 30-L tanks in three replicates per dietary treatment for evaluation of growth performance. Another set of postlarvae (mean initial body weight of 1.25 AE 0.02 g) was randomly distributed in 95-L tanks in three replicates per dietary treatment for the assessment of immune response. Results showed that specific growth rate was significantly higher (P < 0.05) in postlarvae fed D4 and D6. Variations in values for carcass protein, lipid, moisture and ash were also evident. Postlarvae fed diets with Chlorella showed increased prophenol oxidase activity and total haemocyte counts. Moreover, survival rate after challenge with A. hydrophila was significantly increased (P < 0.05). Inclusion of C. vulgaris in diets enhanced immune response and resistance of M. rosenbergii postlarvae against A. hydrophila infection.