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PBB fed to immature chickens: its effect on organ weights and function and on the cardiovascular system
Insights
Polybrominated biphenyls (PBBs) negatively impact chick growth and organ weights, causing reduced feed intake and physiological disturbances. This study details PBBs' toxic effects on White Leghorn cockerels, highlighting critical health concerns.
Area of Science:
- Toxicology
- Animal Science
- Environmental Health
Background:
- Polybrominated biphenyls (PBBs) are persistent organic pollutants with known toxic effects.
- Understanding PBBs' impact on avian physiology is crucial for assessing environmental risks.
Purpose of the Study:
- To investigate the physiological and organ weight effects of chronic PBB exposure in White Leghorn cockerel chicks.
- To differentiate PBBs' direct toxic effects from those secondary to reduced feed intake.
Main Methods:
- Chicks were fed diets containing 50-250 ppm of commercial-grade hexabromobiphenyl (PBB).
- Physiological parameters (growth, thyroid function, ECG, cardiac output, blood pressure, hematocrit, erythropoietin) and organ weights were measured.
- Histological examination of tissues was performed.
- Pair-feeding studies were utilized to control for reduced feed intake.
Main Results:
- Chronic PBB administration led to depressed body weight, decreased comb, testes, spleen, and bursa weights.
- Liver and thyroid weights increased; hydropericardium and ascites were observed.
- Hematological values decreased due to reduced erythropoietin levels; heart rate, packed cell volume, hemoglobin, and cardiac output were reduced.
- ECG showed decreased voltage amplitude and a shifted mean electrical axis; blood pressure and respiratory rate remained unaffected.
Conclusions:
- PBBs exert significant toxic effects on White Leghorn cockerels, impacting growth, organ systems, and cardiovascular function.
- Reduced feed intake is a contributing factor, but PBBs also have direct detrimental physiological effects.
- The findings underscore the need for monitoring and managing PBB contamination to protect animal health and ecosystems.
Abstract:
In a series of polybrominated biphenyl (PBB) feeding trials in White Leghorn cockerel chicks, the effects of PBB on various physiological parameters and organ weights were determined. These measurements included: growth, thyroid function, ECG, cardiac output, blood pressure, hematocrit, erythropoietin levels, and spleen, bursa of Fabricius, thyroid, testes, comb, liver weights. In addition, tissues were histologically examined. PBB, in the commercial grade form of hexabromobiphenyl, was administered continuously in the diet at levels ranging from 50 to 250 ppm. Pair-feeding studies were conducted to ascertain the effects of the drug per se since preliminary trials indicated that PBB administration resulted in decreased feed intake. Chronic administration resulted in depressed body weight as a result of decreased feed intake; decreased comb, testes, spleen, and bursa weights; increased liver and thyroid weight; hydropericardium and ascites; decreased hematological values due to depressed plasma erythropietin levels; decreased heart rate, packed cell volume, hemoglobin and cardiac output; decreased voltage amplitude of the ECG and a shift in the mean electrical axis. No significant differences were found in blood pressure (mean arterial and pulse pressure), stroke volume, or respiratory rate.