The Effects of FKBP12 Single-Dose Plasmid Oral Preparation on the Alkaline Phosphatase Activity, Mortality Rate, and Cocoon Quality of Bivoltine Jinqiu × Churi Silkworms

Sep 30, 2026

Naturally colored silk is valued as a textile and biomedical material, yet some bivoltine silkworm varieties like Jinqiu × Churi show a relatively low cocoon shell ratio that restricts economic output. This study evaluates a recombinant pIEx-1-FKBP12B plasmid delivered as a single oral dose to larvae at different instars to improve survival and cocoon quality. Optimal conditions were identified using alkaline phosphatase activity, mortality rate, cocoon shell weight and ratio, and silk weight. The second-instar group receiving 5 µg showed markedly higher ALP activity and fifth instar larval body length, with increased shell and silk measures and reduced mortality versus control and wild-plasmid groups. Results indicate strong potential for oral plasmid delivery to enhance silk quality.

LanguageEnglish

CategoryHealthcare

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Pages20

Reading Time50 min

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Article The Effects of FKBP12 Single-Dose Plasmid Oral Preparation on the Alkaline Phosphatase Activity, Mortality Rate, and Cocoon Quality of Bivoltine Jinqiu × Churi Silkworms Jiaqi Chen , Ziyu Song, Wenbin Li, Haoyang Feng, Yani Wang, Dajin Wang and Si Li * Academic Editor: Manickam Sugumaran Received: 10 November 2025 Revised: 16 December 2025 Accepted: 19 December 2025 Published: 25 December 2025 Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; [2022332864003@mails.zstu.edu.cn](2022332864003@mails.zstu.edu.cn) (J.C.); [2022332864061@mails.zstu.edu.cn](2022332864061@mails.zstu.edu.cn) (Z.S.); [2023332864062@mails.zstu.edu.cn](2023332864062@mails.zstu.edu.cn) (W.L.); [2023332864067@mails.zstu.edu.cn](2023332864067@mails.zstu.edu.cn) (H.F.); [2023331200065@mails.zstu.edu.cn](2023331200065@mails.zstu.edu.cn) (Y.W.); [wangdj@zstu.edu.cn](wangdj@zstu.edu.cn) (D.W.) * Correspondence: [sili@zstu.edu.cn](sili@zstu.edu.cn) Abstract Although naturally colored silk is an excellent textile material and biomedical material, some silkworm varieties—such as the bivoltine strain Jinqiu × Churi—exhibit a relatively low cocoon shell ratio, which limits their economic value. This study, therefore, aimed to develop a novel approach to enhance larval survival and cocoon quality by orally administering a single dose of a recombinant pIEx-1-FKBP12B plasmid to silkworm larvae at different instars. The optimal feeding larval stages and dosage were evaluated based on the enhancement of alkaline phosphatase activity, mortality rate, cocoon shell weight, cocoon shell ratio, and silk weight. The best results were observed in the group that received a single oral dose of 5 µg of recombinant pIEx-1-FKBP12B plasmid during the second instar. This group exhibited significantly higher alkaline phosphatase activity and fifth instar larval body length compared to the group receiving wild plasmid pIEx-1 . The cocoon shell weight was 21.96% higher, the cocoon shell ratio was 2.5% higher, and the silk weight was 33.60% higher than that of the control group. The mortality rate was the lowest among all the groups, 36.89% lower than the control group. These findings suggest that oral administration of the pIEx-1-FKBP12B plasmid has significant potential for application in improving silk quality. Keywords: silkworm; alkaline phosphatase; FKBP12; cocoon shell ratio; plasmid; oral delivery 1. Introduction Silk has found applications in the textile industry, biological medicine, and tissue engineering due to its extraordinary mechanical properties, biocompatibility, and biodegradability [1–4] . Naturally colored domestic silks (NCSs) are particularly prized for these applications as they eliminate the need for chemical dyeing [5] . These silks are produced by specific genes that transfer pigments from mulberry leaves to the silk gland, and exhibit a fundamental structure and properties similar to common white silk [6] . Jinqiu × Churiis a new silkworm variety developed at Zhejiang University, which received crop variety approval from Zhejiang Province in January 2017 (approval number: Zhejiang province 2017001) . The cocoon of this variety is naturally yellow and is very popular because it does not require chemical dyeing [7]; however, it suffers from a relatively low cocoon shell ratio. The economic value of silkworm rearing is reflected in the proportion of cocoon shell to cocoon weight and the quality of the cocoon shell [8] . Previous experiments conducted by this research group demonstrated that upregulating the FK506 binding protein 12 (FKBP12B) gene (GenBank accession no. DQ443423) in both BmN cells and silkworm larvae significantly and rapidly enhances alkaline phosphatase (ALP) e

FAQs

What problem does the study address in Jinqiu × Churi silkworms?

The study targets the relatively low cocoon shell ratio in the Jinqiu × Churi bivoltine strain, which limits economic value.

How was FKBP12B administered in this study?

A single dose of the recombinant pIEx-1-FKBP12B plasmid was orally administered to silkworm larvae at different instars.

What feeding regimen produced the best results?

The best outcomes were observed in the second instar group receiving a single oral dose of 5 µg of the recombinant pIEx-1-FKBP12B plasmid.

Sep 30, 2026

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